The definition of gregarious is people or animals that are very social and enjoy being in crowds.(adjective)
See gregarious in Webster's New World College Dictionary
Origin: L gregarius, belonging to a flock < grex (gen. gregis), a flock, herd < IE base *ger-, to collect > Gr ageirein, to assemble
See gregarious in American Heritage Dictionary 4
Origin: Latin gregārius, belonging to a flock
Origin: , from grex, greg-, flock; see ger- in Indo-European roots.
Learn more about gregarious