Example : ‘love’, ‘cricket’, ‘sky’ etc.
“[A word is the] smallest unit of grammar that can stand alone as a complete utterance, separated by spaces in written language and potentially by pauses in speech.”(David Crystal, The Cambridge Encyclopedia of the English Language. Cambridge University Press, 2003)
Morphology, a branch of linguistics, studies the formation of words. The branch of linguistics that studies the meaning of words is called lexical semantics.