---
title: keystone — school dictionary · trees and pragmatics
description: «keystone» in the school dictionary: A keystone is the central wedge-shaped stone at the top of an arch that holds all the other stones in place. Every meaning for a pupil with its dependency tree and pragmatics.
---

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# keystone

<!-- .vintro -->
**Who acts:** keystone, arch, everything, keystone species, whole ecosystem, builders · **What happens:** shape, be, hold, depend, put, remove · **To what, where:** central shaped stone, top, other stones, place, important part, idea

<!-- .vabout -->
«keystone» in the school dictionary: its 3 meanings for a pupil and its 6 examples, every sentence parsed by Mova itself — its syntax tree, a dependency tree in the style of Universal Dependencies, and its pragmatics clause by clause. The word in the dictionary, with its sense in the lessons: [keystone in the school dictionary](https://md.mova.elamur.ai/free/en/dictionaries/school/w/keystone.md).

## Meaning 1 {#m1}

<!-- .ven lang=en -->
A keystone is the central wedge-shaped stone at the top of an arch that holds all the other stones in place.

<!-- fold The tree, 22 words -->
```conllu
# sent_id = dict:school:keystone:m1:1
# text = A keystone is the central wedge-shaped stone at the top of an arch that holds all the other stones in place.
1	A	a	DET	DT	Definite=Ind|PronType=Art	2	det	_	_
2	keystone	keystone	NOUN	NN	Number=Sing	9	nsubj	_	_
3	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	9	cop	_	_
4	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
5	central	central	ADJ	JJ	Degree=Pos	9	amod	_	_
6	wedge	wedge	NOUN	NN	Number=Sing	8	compound	_	SpaceAfter=No
7	-	-	PUNCT	HYPH	_	6	punct	_	SpaceAfter=No
8	shaped	shape	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	9	amod	_	_
9	stone	stone	NOUN	NN	Number=Sing	0	root	_	_
10	at	at	ADP	IN	_	12	case	_	_
11	the	the	DET	DT	Definite=Def|PronType=Art	12	det	_	_
12	top	top	NOUN	NN	Number=Sing	9	nmod	_	_
13	of	of	ADP	IN	_	15	case	_	_
14	an	a	DET	DT	Definite=Ind|PronType=Art	15	det	_	_
15	arch	arch	NOUN	NN	Number=Sing	12	nmod	_	_
16	that	that	PRON	WDT	PronType=Rel	17	nsubj	_	_
17	holds	hold	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	15	acl:relcl	_	_
18	all	all	DET	PDT	PronType=Tot	21	det:predet	_	_
19	the	the	DET	DT	Definite=Def|PronType=Art	21	det	_	_
20	other	other	ADJ	JJ	Degree=Pos	21	amod	_	_
21	stones	stone	NOUN	NNS	Number=Plur	17	obj	_	_
22	in	in	ADP	IN	_	23	case	_	_
23	place	place	NOUN	NN	Number=Sing	21	nmod	_	SpaceAfter=No
24	.	.	PUNCT	.	_	9	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **shape** | participle |  |  |  |  |  |  | vn build-26.1-1 «NP.asset V NP»: agent=Asset |
| 2 | **is a** | present | a keystone | the central shaped stone |  | the top of a arch |  |  | tree rules |
| 3 | **hold** | present | a arch | all other stones |  | place |  |  | vn keep-15.2 «NP V NP PP.location»: agent=Agent stone=Theme in place=Location |

<!-- .note -->
One row per clause the reader finds. «not said here»: a role filled from the clause above. «roles by»: a VerbNet class and frame when one fits the verb, else the reader's rules on the tree.

## Meaning 2 {#m2}

<!-- .ven lang=en -->
A keystone is the most important part of a plan, idea or system, which everything else depends on.

<!-- fold The tree, 18 words -->
```conllu
# sent_id = dict:school:keystone:m2:1
# text = A keystone is the most important part of a plan, idea or system, which everything else depends on.
1	A	a	DET	DT	Definite=Ind|PronType=Art	2	det	_	_
2	keystone	keystone	NOUN	NN	Number=Sing	7	nsubj	_	_
3	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	7	cop	_	_
4	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
5	most	most	ADV	RBS	Degree=Sup	6	advmod	_	_
6	important	important	ADJ	JJ	Degree=Pos	7	amod	_	_
7	part	part	NOUN	NN	Number=Sing	0	root	_	_
8	of	of	ADP	IN	_	10	case	_	_
9	a	a	DET	DT	Definite=Ind|PronType=Art	10	det	_	_
10	plan	plan	NOUN	NN	Number=Sing	7	nmod	_	SpaceAfter=No
11	,	,	PUNCT	,	_	12	punct	_	_
12	idea	idea	NOUN	NN	Number=Sing	7	parataxis	_	_
13	or	or	CCONJ	CC	_	14	cc	_	_
14	system	system	NOUN	NN	Number=Sing	12	conj	_	SpaceAfter=No
15	,	,	PUNCT	,	_	19	punct	_	_
16	which	which	PRON	WDT	PronType=Rel	19	obj	_	_
17	everything	everything	PRON	NN	Number=Sing|PronType=Tot	19	nsubj	_	_
18	else	else	ADV	RB	_	17	advmod	_	_
19	depends	depend	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	12	parataxis	_	_
20	on	on	ADV	RB	_	19	advmod	_	SpaceAfter=No
21	.	.	PUNCT	.	_	7	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is a** | present | a keystone | the important part |  |  |  | of a plan | tree rules |
| 2 | **depend** | present | everything | idea or system |  |  |  |  | tree rules |

## Meaning 3 {#m3}

<!-- .note -->
Usage: science — kept apart, not parsed.

<!-- .ven lang=en -->
A keystone species is an animal or plant that its whole ecosystem depends on, like sea otters or beavers.

<!-- fold The tree, 19 words -->
```conllu
# sent_id = dict:school:keystone:m3:1
# text = A keystone species is an animal or plant that its whole ecosystem depends on, like sea otters or beavers.
1	A	a	DET	DT	Definite=Ind|PronType=Art	3	det	_	_
2	keystone	keystone	NOUN	NN	Number=Sing	3	compound	_	_
3	species	species	NOUN	NN	Number=Sing	6	nsubj	_	_
4	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	6	cop	_	_
5	an	a	DET	DT	Definite=Ind|PronType=Art	6	det	_	_
6	animal	animal	NOUN	NN	Number=Sing	0	root	_	_
7	or	or	CCONJ	CC	_	8	cc	_	_
8	plant	plant	NOUN	NN	Number=Sing	6	conj	_	_
9	that	that	SCONJ	IN	_	13	mark	_	_
10	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	12	nmod:poss	_	_
11	whole	whole	ADJ	JJ	Degree=Pos	12	amod	_	_
12	ecosystem	ecosystem	NOUN	NN	Number=Sing	13	nsubj	_	_
13	depends	depend	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	6	advcl	_	_
14	on	on	ADV	RB	_	13	advmod	_	SpaceAfter=No
15	,	,	PUNCT	,	_	18	punct	_	_
16	like	like	ADP	IN	_	18	case	_	_
17	sea	sea	NOUN	NN	Number=Sing	18	compound	_	_
18	otters	otter	NOUN	NNS	Number=Plur	13	obl	_	_
19	or	or	CCONJ	CC	_	20	cc	_	_
20	beavers	beaver	NOUN	NNS	Number=Plur	18	conj	_	SpaceAfter=No
21	.	.	PUNCT	.	_	6	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is a** | present | a keystone species | a animal or plant |  |  |  |  | tree rules |
| 2 | **depend** | present | species's whole ecosystem |  |  |  |  | like sea otters or beavers | vn rely-70 «NP V PP.theme S\_ING»: agent=Agent |

## Example 1 {#x1}

<!-- .ven lang=en -->
The keystone at the top holds the whole arch together.

```conllu
# sent_id = dict:school:keystone:x1:1
# text = The keystone at the top holds the whole arch together.
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	keystone	keystone	NOUN	NN	Number=Sing	6	nsubj	_	_
3	at	at	ADP	IN	_	5	case	_	_
4	the	the	DET	DT	Definite=Def|PronType=Art	5	det	_	_
5	top	top	NOUN	NN	Number=Sing	2	nmod	_	_
6	holds	hold	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
8	whole	whole	ADJ	JJ	Degree=Pos	9	amod	_	_
9	arch	arch	NOUN	NN	Number=Sing	6	obj	_	_
10	together	together	ADV	RB	_	6	advmod	_	SpaceAfter=No
11	.	.	PUNCT	.	_	6	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **hold** | present | the keystone at the top | the whole arch |  |  |  | together *property* | vn keep-15.2 «NP V NP»: agent=Agent arch=Theme |

## Example 2 {#x2}

<!-- .ven lang=en -->
When the builders put in the keystone, they could remove the wooden frame.

<!-- fold The tree, 13 words -->
```conllu
# sent_id = dict:school:keystone:x2:1
# text = When the builders put in the keystone, they could remove the wooden frame.
1	When	when	ADV	WRB	PronType=Int	4	advmod	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	builders	builder	NOUN	NNS	Number=Plur	4	nsubj	_	_
4	put	put	VERB	VBD	Mood=Ind|Number=Plur|Person=3|Tense=Past|VerbForm=Fin	11	advcl	_	_
5	in	in	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	keystone	keystone	NOUN	NN	Number=Sing	4	obl	_	SpaceAfter=No
8	,	,	PUNCT	,	_	4	punct	_	_
9	they	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	11	nsubj	_	_
10	could	could	AUX	MD	VerbForm=Fin	11	aux	_	_
11	remove	remove	VERB	VB	VerbForm=Inf	0	root	_	_
12	the	the	DET	DT	Definite=Def|PronType=Art	14	det	_	_
13	wooden	wooden	ADJ	JJ	Degree=Pos	14	amod	_	_
14	frame	frame	NOUN	NN	Number=Sing	11	obj	_	SpaceAfter=No
15	.	.	PUNCT	.	_	11	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **put** | past | the builders |  |  | the keystone |  |  | vn put-9.1-2 «NP V NP PP.destination»: agent=Agent in keystone=Destination |
| 2 | **remove** | could | builders *= builder* | the wooden frame |  |  |  |  | vn fire-10.10 «NP V NP»: agent=Agent frame=Theme |

## Example 3 {#x3}

<!-- .ven lang=en -->
Sea otters are a keystone species because they eat sea urchins that destroy kelp forests.

<!-- fold The tree, 15 words -->
```conllu
# sent_id = dict:school:keystone:x3:1
# text = Sea otters are a keystone species because they eat sea urchins that destroy kelp forests.
1	Sea	sea	NOUN	NN	Number=Sing	2	compound	_	_
2	otters	otter	NOUN	NNS	Number=Plur	6	nsubj	_	_
3	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	6	cop	_	_
4	a	a	DET	DT	Definite=Ind|PronType=Art	6	det	_	_
5	keystone	keystone	NOUN	NN	Number=Sing	6	compound	_	_
6	species	species	NOUN	NN	Number=Sing	0	root	_	_
7	because	because	SCONJ	IN	_	9	mark	_	_
8	they	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	9	nsubj	_	_
9	eat	eat	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	6	advcl	_	_
10	sea	sea	NOUN	NN	Number=Sing	11	compound	_	_
11	urchins	urchin	NOUN	NNS	Number=Plur	9	obj	_	_
12	that	that	PRON	WDT	PronType=Rel	13	nsubj	_	_
13	destroy	destroy	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	11	acl:relcl	_	_
14	kelp	kelp	NOUN	NN	Number=Sing	15	compound	_	_
15	forests	forest	NOUN	NNS	Number=Plur	13	obj	_	SpaceAfter=No
16	.	.	PUNCT	.	_	6	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is a** | present | Sea otters | a keystone species |  |  |  |  | tree rules |
| 2 | **eat** | present | otters *= otter* | sea urchins |  |  |  |  | vn eat-39.1-1 «NP V NP»: agent=Agent urchin=Patient |
| 3 | **destroy** | present | sea urchins | kelp forests |  |  |  |  | vn destroy-44 «NP V NP»: agent=Agent forest=Patient |

## Example 4 {#x4}

<!-- .ven lang=en -->
Reading is the keystone of learning.

```conllu
# sent_id = dict:school:keystone:x4:1
# text = Reading is the keystone of learning.
1	Reading	reading	NOUN	NN	Number=Sing	4	nsubj	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	cop	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	keystone	keystone	NOUN	NN	Number=Sing	0	root	_	_
5	of	of	ADP	IN	_	6	case	_	_
6	learning	learning	NOUN	NN	Number=Sing	4	nmod	_	SpaceAfter=No
7	.	.	PUNCT	.	_	4	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is a** | present | Reading | the keystone |  |  |  | of learning | tree rules |

## Example 5 {#x5}

<!-- .ven lang=en -->
Beavers are a keystone species that build dams and make ponds.

```conllu
# sent_id = dict:school:keystone:x5:1
# text = Beavers are a keystone species that build dams and make ponds.
1	Beavers	beaver	NOUN	NNS	Number=Plur	5	nsubj	_	_
2	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	5	cop	_	_
3	a	a	DET	DT	Definite=Ind|PronType=Art	5	det	_	_
4	keystone	keystone	NOUN	NN	Number=Sing	5	compound	_	_
5	species	species	NOUN	NN	Number=Sing	0	root	_	_
6	that	that	PRON	WDT	PronType=Rel	7	nsubj	_	_
7	build	build	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	5	acl:relcl	_	_
8	dams	dam	NOUN	NNS	Number=Plur	7	obj	_	_
9	and	and	CCONJ	CC	_	10	cc	_	_
10	make	make	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	7	conj	_	_
11	ponds	pond	NOUN	NNS	Number=Plur	10	obj	_	SpaceAfter=No
12	.	.	PUNCT	.	_	5	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is a** | present | Beavers | a keystone species |  |  |  |  | tree rules |
| 2 | **build** | present | a keystone species | dams |  |  |  |  | vn build-26.1-1 «NP.asset V NP»: agent=Asset dam=Product |
| 3 | **make** | present | a keystone species *not said here* | ponds |  |  |  |  | vn build-26.1-1 «NP.asset V NP»: agent=Asset pond=Product |

## Example 6 {#x6}

<!-- .ven lang=en -->
Pennsylvania is known as the Keystone State.

```conllu
# sent_id = dict:school:keystone:x6:1
# text = Pennsylvania is known as the Keystone State.
1	Pennsylvania	Pennsylvania	PROPN	NNP	Number=Sing	3	nsubj:pass	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	aux:pass	_	_
3	known	know	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	_	_
4	as	as	ADP	IN	_	7	case	_	_
5	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
6	Keystone	Keystone	PROPN	NNP	Number=Sing	7	compound	_	_
7	State	State	PROPN	NNP	Number=Sing	3	obl	_	SpaceAfter=No
8	.	.	PUNCT	.	_	3	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **know** | present · passive |  | Pennsylvania |  |  |  | as the Keystone State | vn comprehend-87.2-1-1-1 «NP V NP PP.attribute»: subject=Stimulus as state=Attribute |

<!-- div src -->

**Text:** the school dictionary of Mova's schools (`world/data/dictionary-schools/`), written for Mova. **Trees:** Mova's own parse — the `en` model on the CPU, when the site is built — not checked by a teacher; they may be wrong. **Frames:** Mova's frames reader (`prag`), each meaning and example read on its own. Elamur Cosmic License.

<!-- /div -->

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