split second
noun [ S ] uk/ˌsplɪt ˈsek.ənd/ us/ˌsplɪt ˈsek.ənd/
一瞬间，一刹那
a very short moment of time
They brought out guns and for a split second nobody moved. 他们拔出了枪，一刹那间没有人敢动。
We had to make a split-second (= very quick) decision. 我们得迅速作出决定。
Synonyms: flash heartbeatinstant jiffy moment (SHORT TIME)in a trice