What is the word that denotes the words preceding these nouns?

What word describes/denotes the words that precede vision in the following two words: computer vision and machine vision?

Solution 1:

The word I hear most is noun adjective, while attributive noun and noun adjunct sound equally appropriate and current. I have never heard noun premodifier, though it sounds technically correct. I might prefer adjectival noun myself despite Wikipedia's reservations. A noun adjective is always a modifier, but not the other way around: modifier is a correct but less specific term.

While Ngrams are mere (defective) statistics and ultimately cannot support any such assertion, they may, when taken with a big lump of 'sea salt,' give readers some indication.

Solution 2:

I know it as an attributive noun, but according to this Wikipedia article, it's also called a noun adjunct or noun premodifier.

Solution 3:

• Q1: What do you call it?

A noun preceding and describing other noun is called a noun adjunct or attributive noun or noun premodifier. Source 1 calls it premodifier.

• Q2: Are they still nouns?

Yes, all the sources call them nouns.

• Q3: Are they adjectives?

From source 3:

Nouns used in this way are sometimes said to be adjectives or to behave like adjectives. Attributive nouns may be marked in dictionaries with a label like often attrib placed after the part-of-speech label for noun. While any noun may be used attributively, the label is limited to those quite frequently used in this manner. An adjective is defined as a word standing for the name of an attribute which describes a noun more fully, e.g., "yellow flower."

Source 1 does not write that a noun can function as an adjective.

• Q4: How can a noun function as an adjective (what is the meaning of function)? Is this a rigorous definition?

More research needed

Notes:
-you can also have postmodifiers

-the premodifiers of nouns are usually adjectives, but they can also be nouns, genitive noun phrases, participles, adverbs, numerals, and others.

Sources I found and consulted:

• 1) Oxford English Grammar, S.Greenbaum

• 2) Wikipedia's Noun Adjunct entry.

• 3) Dictionary.com What is the difference between an attributive noun and an adjective?