We found one dictionary that defines the word first world wars:

General (1 matching dictionary)

1. First World Wars: Collins English Dictionary

(Note: See first_world_war as well.)

Definitions from Wiktionary (First World War) ▸ noun:  World War I. ▸ Also see first_world_war ▸ Words similar to first world wars ▸ Usage examples for first world wars ▸ Idioms related to first world wars ▸ Wikipedia articles (New!) ▸ Words that often appear near first world wars ▸ Rhymes of first world wars ▸ Invented words related to first world wars