Clarification on Latin Terms for Grammar [closed]

I'm studying Classical Arabic at the moment from a book written quite some time ago. It uses Latin names for the various grammatical terms and I am having some difficulty in understanding them.

For example, the terms: nomen substantivium and nomen adjectivum. From what I could gather nomen is Latin for noun? If so then what is nomen adjectivum? I know this is referring to adjectives but what is nomen doing prefixed to adjectivum?

Also what is the difference between nomen demonstrativum and nomen conjunctivium?

Solution 1:

Classical Latin grammarians did not distinguish between adjectives and nouns as 'parts of speech': what we call adjectives could be used as nouns, and adjectives declined the same way nouns did (only in three genders!), so they called them both nomina, our nouns. What they did distinguish (in a very modern way) was uses of the words: a nomen substantivum (substantive noun) was a noun employed to designate an 'entity', something with 'substance', and a nomen adjectivum (adjective noun) was a noun 'set down next to' a substantive as a modifier.

Similarly, a nomen demonstrativum, which 'pointed to' another noun, was what we call a 'demonstrative pronoun', and a nomen conjunctivum, which 'joined' a noun to a clause about it, was what we call a 'relative pronoun'.