The Collaborative International Dictionary
Pentatomic
Pentatomic \Pen`ta*tom"ic\, a. [Penta- + atomic.] (Chem.)
Having five atoms in the molecule.
Having five hydrogen atoms capable of substitution.
Wiktionary
pentatomic
a. 1 (context chemistry English) Having five atoms in each molecule 2 (context chemistry English) Having five hydrogen atoms capable of substitution. alt. 1 (context chemistry English) Having five atoms in each molecule 2 (context chemistry English) Having five hydrogen atoms capable of substitution.