ANHARMONIC

An′har‐mon″ic (�), a. [[F. anharmonique, fr. Gr. αν̓ priv. + � harmonic.]] (Math.) Not harmonic. The anharmonic function or ratio of four points abcd on a straight line is the quantity (ac/ad):(bc/bd), where the segments are to be regarded as plus or minus, according to the order of the letters.