一瞬[isshun] moment
一瞬間[isshunkan] moment
瞬く[matataku] to twinkle (e.g. stars)
瞬間[shunkan] moment
瞬間電断[shunkandendan] power flicker

瞬刻[shunkoku] moment
瞬時[shunji] moment
瞬断[shundan] power flicker
瞬き[mabataki] blink (of eyes)
瞬く間に[matatakumani] in the twinkling of an eye