femtosecond femton • femtovolt · · · Info · Definitions · Characters · · femtosecond · · Text Latin · · Script 11 · · Length 4 · · Syllables Definitions · · · (noun) one quadrillionth (10^-15) of a second; one thousandth of a picosecond. · · Noun Definition 1 Characters · · c latin small letter c U+0063 d latin small letter d U+0064 e latin small letter e U+0065 f latin small letter f U+0066 m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F s latin small letter s U+0073 t latin small letter t U+0074