lexicology vs philology

lexicology and philology both are nouns.

Word	Noun	Adjective	Verb	Adverb
lexicology	Yes	No	No	No
philology	Yes	No	No	No

As nouns, philology is a hypernym of lexicology; that is, philology is a word with a broader meaning than lexicology:

lexicology: the branch of linguistics that studies the lexical component of language
philology: the humanistic study of language and literature

Other hypernyms of lexicology include linguistics.

lexicology (noun)	philology (noun)
the branch of linguistics that studies the lexical component of language	the humanistic study of language and literature