a general sense, denotes some variation in the qualities or circumstances of a thing, without wholly changing its nature.

music, the distance of any interval increased or diminished, which of consequence must sharpen or flatten the chords which these altered intervals compose.

Altern-base, in trigonometry, a term used in contradistinction to the true base. Thus in oblique triangles, the true base is either the sum of the sides, and then the difference of the sides is called the altern-base; or the true base is the difference of the sides, and then the sum of the sides is called the altern-base.