10. (Mus.) (a) A musical idea, or motive, rhythmically developed in consecutive single tones, so as to form a symmetrical and balanced whole, which may be sung by a single voice to the stanzas of a hymn or song, or even to plain prose, or played upon an instrument; a melody; a tune; an aria. (b) In harmonized chorals, psalmody, part songs, etc., the part which bears the tune or melody -- in modern harmony usually the upper part -- is sometimes called the air.
11. The peculiar look, appearance, and bearing of a person; mien; demeanor; as, the air of a youth; a heavy air; a lofty air. "His very air." Shak.