Almucantar n. (Astron.) A small circle of the sphere parallel to the horizon; a circle or parallel of altitude. Two stars which have the same almucantar have the same altitude. See Almacantar. (Archaic) Almucantar staff, an ancient instrument, having an arc of fifteen degrees, formerly used at sea to take observations of the sun's amplitude at the time of its rising or setting, to find the variation of the compass.
