What does "philology" mean?

Philology: The study of language, especially in a philosophical manner and as a science; the investigation of the laws of human speech, the relation of different tongues to one another, and historical development of languages; linguistic science. Note: Philology comprehends a knowledge of the etymology, or origin and combination of words; grammar, the construction of sentences, or use of words in language; criticism, the interpretation of authors, the affinities of different languages, and whatever relates to the history or present state of languages. It sometimes includes rhetoric, poetry, history, and antiquities.