Momentary

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late Middle English: from Latin momentarius, from momentum (see moment).

wiktionary

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From Late Latin mōmentārius(“of brief duration”), from mōmentum(“a short time, an instant”). Synchronically analyzable as moment +‎ -ary.

etymonline

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momentary (adj.)

"lasting but a moment, of short duration," mid-15c., momentare, from Late Latin momentarius "of brief duration," from Latin momentum "a short time, an instant" (see moment).