名詞 millimicron:

1. a metric unit of length equal to one billionth of a meter
   同義詞：nanometer, nanometre, nm, micromillimeter, micromillimetre

mil.li.mi.cron

n.（名詞）
A unit of length equal to one thousandth (0-3) of a micrometer or one billionth (0 -9) of a meter.
毫微米：長度單位，等于千分之一(0-3)微米或十億分之一(0 -9)米