The Collaborative International Dictionary of English v.0.48:
Almucantar \Al`mu*can"tar\, n. [F. almucantarat, almicantarat,
ultimately fr. Ar. al-muqantar[=a]t, pl., fr. qantara to
bend, arch.] (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.
Almucanter 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.