(Pen"tine) n. [See Penta-.] (Chem.) An unsaturated hydrocarbon, C5H8, of the acetylene
series. Same as Valerylene.
(Pen*to"ic) a. [See Penta-.] (Chem.) Pertaining to, or desingating, an acid (called also valeric
acid) derived from pentane.
(Pen"tone) n. [See Penta-.] (Chem.) Same as Valylene.
(Pen*tox"ide) n. [Penta- + oxide.] (Chem.) An oxide containing five atoms of oxygen in
each molecule; as, phosphorus pentoxide, P2O5.
(Pen"tre*mite) n. (Zoöl.) Any species of Pentremites.
(||Pen`tre*mi"tes) n. [NL., from Gr. five + L. remus an oar.] (Zoöl.) A genus of crinoids
belonging to the Blastoidea. They have five petal-like ambulacra.
(Pent"roof`) n. [F. pente slope + E. roof, or from penthouse roof.] See Lean-to.
(Pen"trough`) n. A penstock.
(Pen"tyl) n. [Penta + - yl.] (Chem.) The hypothetical radical, C5H11, of pentane and certain of
its derivatives. Same as Amyl.
(Pen*tyl"ic) a. Pertaining to, derived from, or containing, pentyl; as, pentylic alcohol
(Pe"nu*chle Pin"o*cle) , n. A game at cards, played with forty-eight cards, being all the cards
above the eight spots in two packs.
(Pe"nult) n. [Abbreviated fr. penultima.] (Gram. & Pros.) The last syllable but one of a word; the
syllable preceding the final one.
(Pe*nul"ti*ma) n. [L. (sc. syllaba), fr. penultimus, paenultimus, the last but one; paene
almost + ultimus the last.] Same as Penult.
(Pe*nul"ti*mate) a. Last but one; as, the penultimate syllable, the last syllable but one of a
(Pe*nul"ti*mate), n. The penult.
(Pe*num"bra) n. [NL., fr. L. paene almost + umbra shade.]
1. An incomplete or partial shadow.
2. (Astron.) The shadow cast, in an eclipse, where the light is partly, but not wholly, cut off by the intervening
body; the space of partial illumination between the umbra, or perfect shadow, on all sides, and the full
light. Sir I. Newton.
The faint shade surrounding the dark central portion of a solar spot is also called the penumbra, and
3. (Paint.) The part of a picture where the shade imperceptibly blends with the light.
(Pe*num"brala). Of or pertaining to a penumbra; resembling a penumbra; partially illuminated.
(Pe*nu"ri*ous) a. [From Penury.]