preschooler vs kid

preschooler and kid both are nouns.

Word	Noun	Adjective	Verb	Adverb
preschooler	Yes	No	No	No
kid	Yes	No	Yes	No

As nouns, kid is a hypernym of preschooler; that is, kid is a word with a broader meaning than preschooler:

Other hypernyms of preschooler include child, fry, minor, nestling, nipper, shaver, small fry, tiddler, tike, tyke, youngster.

preschooler (noun)	kid (noun)
a child who attends a preschool or kindergarten	young goat
	a young person of either sex
	a human offspring (son or daughter) of any age
	soft smooth leather from the hide of a young goat

preschooler (verb)	kid (verb)
	be silly or tease one another
	tell false information to for fun