積 雲(せきうん)

せきうん

noun

cumulus cloud

1. cumulus cloud

One of the ten standard cloud genera: puffy, cotton-like clouds with flat bases and rounded tops, typically forming on fair-weather days by thermal convection in the lower atmosphere.

空(そら)に積雲(せきうん)が浮(う)かぶ。

Cumulus clouds float in the sky.

夏(なつ)の午後(ごご)は積雲(せきうん)がよく発達(はったつ)する。

Cumulus clouds often develop well on summer afternoons.

積雲(せきうん)は白(しろ)くて綿(わた)のような形(かたち)をしている。

Cumulus clouds are white and shaped like cotton.

積雲(せきうん)が大(おお)きく発達(はったつ)すると、やがて積乱雲(せきらんうん)になり雷雨(らいう)をもたらすことがある。

When cumulus clouds develop greatly, they can eventually become cumulonimbus and bring thunderstorms.

Composed of 積(せき) (pile up, accumulate) and 雲(うん) (cloud). One of the ten standard cloud classifications (十(じゅう)種(しゅ)雲形(うんけい)) used in meteorology.

Usage

A technical meteorological term but widely recognized in everyday contexts (weather reports, science textbooks).
Used as a plain noun; does not take する.

Common collocations

積雲(せきうん)が発達(はったつ)する: cumulus clouds develop
積雲(せきうん)が浮(う)かぶ: cumulus clouds float (in the sky)
夏(なつ)の積雲(せきうん): summer cumulus clouds

Related words

積乱雲(せきらんうん): cumulonimbus — a towering, thundercloud form developed from cumulus
層雲(そううん): stratus — flat, layered low clouds
巻雲(けんうん): cirrus — wispy high-altitude clouds
入道雲(にゅうどうぐも): thunderhead (colloquial) — everyday word for a large cumulus/cumulonimbus

Related Words

Related: 積乱雲(せきらんうん) (cumulonimbus)

Related: 層雲(そううん) (stratus)

Related: 巻雲(けんうん) (cirrus)

Related: 入道雲(にゅうどうぐも) (thunderhead)

general

Added 2026.4.14 23:04 · Revised 2026.9.2 13:02

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