出典:Wiktionary
Clipping of acycloguanosine + -vir. From being an antiviral (-vir) containing less cyclic structure ("a-"cyclic) than the naturally occurring analogue from which it is based, guanosine. This is analyzable as a- + cyclo- + -vir.
acyclovir (usually uncountable, 複数形 acyclovirs)