: one quadrillionth (10−15) part of
femtosecond

Word History

Etymology

International Scientific Vocabulary, from Danish or Norwegian femten fifteen, from Old Norse fimmtān; akin to Old English fīftēne fifteen

Dictionary Entries Near femto-

Cite this Entry

“Femto-.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/femto-. Accessed 30 Nov. 2024.

More from Merriam-Webster on femto-

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!