Dependency Relations

Nominal Dependents

Seven relations that add detail to a noun: they describe it, count it, name its owner or rename it. In a tree, the noun is the head, so look for arrows that start at a noun and point down. Two rare members, quantmod and nmod, attach to a number instead.

What you’ll learn

Recognise the seven relations of this family and the word each one attaches to
Tell amod from compound by the word class of the modifier
Tell nummod from amod: a counting number (three) or an ordinal (third)
Read a possessive with 's as two arcs (poss and case), and a possessive pronoun as one
Explain why nmod almost never appears here, and name the one construction that produces it

The noun is the head

This family is defined by where a word attaches, not by what kind of word it is. An adjective (old), a noun (chess), a number (three) and a possessive (their) are very different words. But each one attaches to a noun and tells you more about it.

That gives you a quick way to read a tree. Arrows run from a head down to its dependent, so find the nouns first: almost every arrow of this family starts at a noun. All seven relations share one colour, so read the label beside each arrow to tell them apart.

One noun can carry several of these relations at once. The tree below has four of them. Read it in four steps.

“Marta’s three small clay pots cracked.”

poss Possession modifier
case Case marking
nummod Numeric modifier
amod Adjectival modifier
compound Compound
nsubj Nominal subject
ROOT Root of the sentence

One noun, four dependents from this family: poss, nummod, amod and compound all attach to 'pots'

Find the noun
In Marta’s three small clay pots cracked, the subject is the noun pots.
Follow each arrow down from it
Four arrows start at pots. They point down to Marta, three, small and clay.
Name each relation
The owner Marta is poss, and its ’s adds a case arc. The number three is nummod, the adjective small is amod and the noun clay is compound.
Find the whole noun phrase
The noun and every word below it make the noun phrase: Marta’s three small clay pots.

Describing the noun

amod Adjectival modifier

An adjective modifying a noun. It is the most common member of the family, and the easiest to predict.

How the parser decides: an adjective sitting inside a noun phrase, attached to its noun. It makes no difference whether that noun phrase is the subject, the object, or inside a prepositional phrase.

“A crimson banner hung outside.”

det Determiner
amod Adjectival modifier
nsubj Nominal subject
ROOT Root of the sentence
advmod Adverbial modifier

The adjective 'crimson' attaches to 'banner', not to the verb

“He collects antique clocks.”

The same relation inside an object noun phrase

Two adjectives in a row do not attach to each other. Each one attaches to the noun on its own, so the noun gets two separate arcs.

“The old wooden gate creaked.”

The adjectives 'old' and 'wooden' are siblings: both attach to 'gate', not to each other

compound Compound

A noun modifying another noun: bread flour, chess club, kitchen window. English uses this pattern very often. The first noun takes this label, not amod.

How the parser decides: by the tag of the modifier. If the parser tags it as a noun, the label is compound, even when the word seems to work like an adjective.

“The bread flour ran out.”

det Determiner
compound Compound
nsubj Nominal subject
ROOT Root of the sentence
prt Particle

The noun 'bread' modifies 'flour', so the relation is compound

“She joined the chess club.”

The noun 'chess' modifies 'club'; the determiner attaches to 'club' as well

appos Appositional modifier

An appositive is a second noun phrase that renames the first. Our guide and Amara are one person, named twice.

How the parser decides: a noun phrase right after another noun phrase, usually between commas, with no verb or preposition joining them. The label goes on the second one, and its head is the first: the arrow runs from guide down to Amara.

“Our guide, Amara, waited outside.”

poss Possession modifier
nsubj Nominal subject
appos Appositional modifier
ROOT Root of the sentence
advmod Adverbial modifier

'Amara' hangs from 'guide', so the subject of 'waited' is still 'guide'

“She phoned Dr Okafor, her dentist.”

An appositive on an object — 'dentist' renames 'Okafor'

Counting and owning

nummod Numeric modifier

A counting number that modifies a noun: three otters, twelve chairs. It attaches to the noun just as an adjective does, but it has its own label.

How the parser decides: the modifier is a cardinal number. Words and digits are treated the same: twelve chairs and 12 chairs both give nummod.

“Three otters crossed the river.”

nummod Numeric modifier
nsubj Nominal subject
ROOT Root of the sentence
det Determiner
dobj Direct object

'Three' attaches to 'otters', which is itself the subject

“He ordered twelve chairs.”

The same relation inside an object

poss Possession modifier

The owner, or possessor. It attaches to the thing owned: in Priya’s telescope, Priya attaches to telescope, not the reverse. Spanish works the same way (el telescopio de Priya): the head is the thing owned. English just puts the owner first.

How the parser decides: either a possessive pronoun (their, her) or a noun carrying ’s. Both get the same label, poss, attached to the thing owned.

“Priya’s telescope needs repair.”

poss Possession modifier
case Case marking
nsubj Nominal subject
ROOT Root of the sentence
dobj Direct object

Two arcs for one possessive: poss for 'Priya', and case for the 's

The ’s is a separate word to the parser, with its own arc. A possessive pronoun has no ’s to split off, so it has one arc instead of two.

“Their cottage overlooks the bay.”

A possessive pronoun — same relation, no case arc

quantmod Quantifier modifier Rare

A word that modifies a number rather than a noun. It appears inside a quantity of two or more words: than in more than half, or Some (meaning “about”) in Some twenty boats.

How the parser decides: its head is a number, and the word itself is a short word such as than, over, under or some. The number stays nummod, attached to the noun. Other words in the quantity keep their usual labels. The adjective more is amod, and an adverb such as about or nearly (about twenty) is advmod.

“He ate more than half the cake.”

nsubj Nominal subject
ROOT Root of the sentence
amod Adjectival modifier
quantmod Quantifier modifier
nummod Numeric modifier
det Determiner
dobj Direct object

The word 'than' is quantmod and 'more' is amod, both attached to 'half'; 'half' is the nummod of 'cake'

“Some twenty boats sank.”

quantmod Quantifier modifier
nummod Numeric modifier
nsubj Nominal subject
ROOT Root of the sentence

'Some' attaches to the number 'twenty', not to 'boats', so it is quantmod

The label you will almost never see: nmod

nmod Noun modifier Rare

nmod has a colour and a place in this family, but Grammify’s parser uses it for only one construction: a currency sign. In $12, the number is the head and the sign attaches to it as nmod. The same happens with £ and €. In about 60 test sentences, a noun modifying another noun never produced it.

Why so rare? This parser gives each common kind of noun modifier its own label:

a noun right before another noun is compound (kitchen window);
an owner is poss (Priya’s telescope);
a noun after a preposition is pobj, and the preposition is prep (a map of the coast).

Parsers that follow Universal Dependencies use nmod for the last two, so you may meet it in other tools.

“The kitchen window cracked.”

det Determiner
compound Compound
nsubj Nominal subject
ROOT Root of the sentence

The noun 'kitchen' modifies 'window', but its label is compound, not nmod

“Tickets cost $12 for adults.”

The one construction that yields nmod — the currency sign attaches to its number

Quick check

In Priya washed the coffee cups, which word is the head of the coffee cups? Which label does coffee get, amod or compound?
Answer
cups is the head: Priya washed cups, and in an English compound the main noun comes last (Spanish says tazas de café). coffee is a noun, so it gets compound, attached to cups.
In Santiago’s sister sold her car, how many arcs do the two possessives need, and what are their labels?
Answer
Three. Santiago is poss, attached to sister, and ’s is case, attached to Santiago. her is poss, attached to car: a possessive pronoun has no ’s to split off, so it needs only one arc.
Compare Nina won two races with Nina won the third race. Which number word is nummod, and which is amod?
Answer
two is nummod: it counts the races. third is amod: ordinal numbers put things in order, and the parser tags them as adjectives. Each one attaches to its noun (races, race).
The label nmod is glossed “Noun modifier”. In Omar painted the garden wall, the noun garden modifies wall. Is garden nmod?
Answer
No. garden is compound, attached to wall: this parser labels a noun right before another noun compound. It uses nmod for only one construction, a currency sign attached to its number, as in $12.

Key terms

Noun phrase: A noun together with every word below it in the tree. A dependency tree draws no box around it: start at the noun and collect every word under it. The old kettle whistled. She bought a map of the coast.
See: Grammar Basics
Appositive: A noun phrase renaming the one beside it. The second attaches to the first, so the first keeps its role in the sentence. My friend Jacob called. The capital, Lima, is on the coast.
See: Possessives & Appositives
Possessor: Labelled poss, and attached to the thing owned. A ’s is a separate token carrying its own case arc. Omar’s coat is here. Her coat is here.
See: Possessives & Appositives
Compound: A noun used to modify another noun. Distinguished from amod purely by the modifier’s part of speech — see Parts of Speech. The kitchen door stuck. A philosophy professor spoke.

Practice on a real sentence

A long sentence: build its noun phrases first. For each relation from this page, pick its label, click the noun (the head), then click the word that describes it. Which words are poss? Are first and second nummod or amod? The relative clause who was little wiser also attaches to a noun, but its label, relcl, belongs to Modifier Relations.

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