Ses`qui*al"ter*al (?), Ses`qui*al"ter*ate (?), a. [L. sesquialter once and a half; sesqui- + alter other: cf. F. sesquialt'ere.]
Once and a half times as great as another; having the ratio of one and a half to one.
Sesquialteral ratio Math., the ratio of one and a half to one; thus, 9 and 6 are in a sequialteral ratio.
© Webster 1913.