multitudinous adj.

"a great number regarded collectively; a crowd or throng; the characteristic of being many, numerousness," early 14c., from Old French multitude (12c.) and directly from Latin multitudinem (nominative multitudo) "a great number, a crowd; the crowd, the common people," from multus "many, much" (see multi-) + suffix -tudo (see -tude). Related: Multitudes.

A multitude, however great, may be in a space so large as to give each one ample room; a throng or a crowd is generally smaller than a multitude, but is gathered into a close body, a throng being a company that presses together or forward, and a crowd carrying the closeness to uncomfortable physical contact. [Century Dictionary]

word-forming element making adjectives from nouns, meaning "having, full of, having to do with, doing, inclined to," from Old French -ous, -eux, from Latin -osus (compare -ose (1)). In chemistry, "having a lower valence than forms expressed in -ic."