Definition of pentatomic in English:

pentatomic

(also penta-atomic)

adjective

Chemistry
  • Consisting of five atoms; containing five atoms per molecule.

Origin

Mid 19th century; earliest use found in Henry Watts (1815–1884), chemist. From penta- + atomic [noun].

Pronunciation

pentatomic

/ˌpɛntəˈtɒmɪk/