The definition of later is afterward.
(adverb)An example of the use of later as an adverb is in the sentence, "We will go later," which means we will go at a future time.
Later is defined as an informal way of saying bye.
(interjection)An example of the use of later as an interjection is in the sentence, "I'm leaving now! Later!" which means, "I'm leaving now! Goodbye!"
See later in Webster's New World College Dictionary
adjective
adverb
See later in American Heritage Dictionary 4
Learn more about later