Pentacron
(Pen*ta"cron) n.; pl. L. Pentacra E. Pentacrons [NL., fr. Gr. five + a summit.] (Geom.) A
solid having five summits or angular points.
Pentacrostic
(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.
Pentad
(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.
Pentad
(Pen"tad), a. (Chem.) Having the valence of a pentad.
Pentadactyl
(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.
2. Having five appendages resembling fingers or toes.
Pentadactyloid
(Pen`ta*dac"tyl*oid) a. [Pentadactyl + -oid.] (Anat.) Having the form of, or a structure
modified from, a pentadactyl limb.
Pentadecane
(Pen`ta*dec"ane) n. [Penta- + Gr. ten.] (Chem.) A hydrocarbon of the paraffin series,
(C15H32) found in petroleum, tar oil, etc., and obtained as a colorless liquid; — so called from the fifteen
carbon atoms in the molecule.
Pentadecatoic
(Pen`ta*dec`a*to"ic) a. [Penta- + decatoic.] (Chem.) Of, pertaining to, or derived from,
pentadecane, or designating an acid related to it.
Pentadecylic
(Pen`ta*decyl"ic) a. [Penta- + decylic.] (Chem.) Same as Quindecylic.
Pentadelphous
(Pen`ta*del"phous) a. [Penta- + Gr. brother.] (Bot.) Having the stamens arranged
in five clusters, those of each cluster having their filaments more or less united, as the flowers of the
linden.
Pentafid
(Pen"ta*fid) a. [Penta- + root of L. findere to split.] (Bot.) Divided or cleft into five parts.
Pentaglot
(Pen"ta*glot) n. [Penta- + -glot, as in polyglot.] A work in five different tongues.
Pentagon
(Pen"ta*gon) n. [Gr. (see Penta-) + gwni`a angle: cf. L. pentagonium, F. pentagone.] (Geom.)
A plane figure having five angles, and, consequently, five sides; any figure having five angles.
Regular pentagon,
a pentagon in which the angles are all equal, and the sides all equal.
Pentagonal
(Pen*tag"o*nal) a. [Cf. F. pentagonal, pentagone, L. pentagonus, pentagonius, Gr. .]
Having five corners or angles.
Pentagonal dodecahedron.
See Dodecahedron, and Pyritohedron.
Pentagonally
(Pen*tag"o*nal*ly), adv. In the form of a pentagon; with five angles. Sir T. Browne.
Pentagonous
(Pen*tag"o*nous) a. Pentagonal.
Pentagram
(Pen"ta*gram) n. [Gr. neut. of having five lines. See Penta-, and -gram.] A pentacle or a
pentalpha. "Like a wizard pentagram." Tennyson.