- five: pentagon, pentameter, pentaprism
WordReference Random House Learner's Dictionary of American English © 2026
penta-, prefix.
WordReference Random House Unabridged Dictionary of American English © 2026- penta- comes from Greek, where it has the meaning "five'':penta- + -gon → pentagon (= five-sided figure).
penta-,
- a combining form occurring in loanwords from Greek, meaning "five'' (Pentateuch);
on this model, used in the formation of compound words (pentavalent).
- Greek pent-, penta-, comb. forms representing pénte five
Collins Concise English Dictionary © HarperCollins Publishers::
penta- combining form
'penta-' also found in these entries (note: many are not synonyms or translations):
pentacle
- Pentateuch
- pentathlon
- pentode
- pentstemon
- peta-
- cyclopentadiene
- eicosapentaenoic acid
- Hexateuch
- pentachloronitrobenzene
- pentachlorophenol
- pentadactyl
- pentadecagon
- pentaerythritol
- pentagon
- pentagram
- pentahedron
- pentahydrate
- pentahydric
- pentahydroxy
- pentamerous
- pentameter
- pentamethylene
- pentamethylenediamine
- pentaploid
- pentapody
- pentaprism
- pentaptych
- pentastich
- pentastomid
- pentastyle
- pentasyllable
- pentatonic scale
- pentavalent
- pentazocine