rontosecond

== English == === Etymology === From ronto- +‎ second. === Pronunciation === (General American) IPA(key): /ˈɹɑn.toʊˌsɛk.ənd/ === Noun === rontosecond (plural rontoseconds) (metrology) An SI unit of time equal to 10−27 seconds. Symbol: rs Alternative form: rs (symbol)