Search Result for "femtosecond": 
Wordnet 3.0

NOUN (1)

1. one quadrillionth (10^-15) of a second; one thousandth of a picosecond; 



WordNet (r) 3.0 (2006):

femtosecond
    n 1: one quadrillionth (10^-15) of a second; one thousandth of a
         picosecond