How to say "momentum" in Japanese

• 余勢よせいCommon
  nounCovers momentum in the sense of surplus power or inertia left over from an action — the force that carries something onward after the initial effort. Often suggests riding on the impetus of a previous success or movement.
• はずみCommon
  nounThe everyday choice for momentum as forward drive or impetus, whether physical or figurative; it also means impulse and stimulus. Since it is normally written in kana alone, prefer the kana spelling.
  ドル安やすは輸出ゆしゅつにはずみをつけています。↗

  The cheap dollar is charging up exports.
• 機運きうんCommon
  nounMeans momentum only in the metaphorical sense of a favourable trend or rising tendency, as in growing public enthusiasm or a business climate. For physical movement, this is not the word you want.

Use 「はずみ」 for physical or impulsive momentum, 余勢 for the surplus force carried over from an action, and 機運 when the momentum is metaphorical, meaning a favourable trend or climate of opinion.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 余勢よせいsurplus power
• モーメンタムmomentum
• 行き足ゆきあしmomentum (e.g. of a boat)
• モーメント項モーメントこうmomentum
• 運動量うんどうりょうmomentum
• 動量どうりょうmomentum
• 気運きうんtrend
• 惰力だりょくinertia
• 勢いいきおいimpetus
• はずみmomentum
• 機運きうんtrend