content word

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A word, such as a noun, verb, or adjective, that has a statable lexical meaning, rather than indicating a syntactic function, as a function word does.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun linguistics A word that is not a function word, including nouns, verbs, adjectives, and most adverbs with the exception of the likes of "then" and "why".

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a word to which an independent meaning can be assigned