Pen*tac"id (&?;), a. [Penta- + acid.] (Chem.) Capable of neutralizing,
or combining with, five molecules of a monobasic acid; having five
hydrogen atoms capable of substitution by acid residues; -- said of
certain complex bases.
Pen"ta*cle (?), n. [Gr. &?; five.] A figure composed of two equilateral
triangles intersecting so as to form a six-pointed star, -- used in
early ornamental art, and also with superstitious import by the
astrologers and mystics of the Middle Ages.
Pen`ta*coc"cous (?), a. [See Penta- , Coccus.] (Bot.) Composed of five
united carpels with one seed in each, as certain fruits.
Pen"ta*con`ter (?), n. (Gr. Antiq.) See Penteconter.
Pen*tac"ri*nin (?), n. (Physiol. Chem.) A red and purple pigment found
in certain crinoids of the genus Pentacrinus.
Pen*tac"ri*nite (?), n. [Penta- + Gr. &?; a lily.] (Zoˆl.) Any species
of Pentacrinus.
Pen*tac"ri*noid (?), n. [Pentacrinus + -oid.] (Zoˆl.) An immature
comatula when it is still attached by a stem, and thus resembles a
Pentacrinus.
||Pen*tac"ri*nus (?), n. [NL. See Penta-, and Crinum.] (Zoˆl.) A genus
||of large, stalked crinoids, of which several species occur in deep
||water among the West Indies and elsewhere.
Pen*ta"cron (?), n.; pl. L. Pentacra (#), E. Pentacrons (#). [NL., fr.
Gr. &?; five + &?; a summit.] (Geom.) A solid having five summits or
angular points.
Pen`ta*cros"tic (?), n. [Penta- + acrostic.] A set of verses so
disposed that the name forming the subject of the acrostic occurs five
times -- the whole set of verses being divided into five different
parts from top to bottom.
Pen"tad (?), n. [Gr. &?;, &?;, a body of five, fr. &?; five.] (Chem.)
Any element, atom, or radical, having a valence of five, or which can
be combined with, substituted for, or compared with, five atoms of
hydrogen or other monad; as, nitrogen is a pentad in the ammonium
compounds.
Pen"tad, a. (Chem.) Having the valence of a pentad.
{ Pen`ta*dac"tyl, Pen`ta*dac"tyle } (?), a. [Gr. &?; with five fingers
or toes. See Penta- , and Dactyl.] 1. (Anat.) Having five digits to the
hand or foot.