気泡|きほうkihou[0]heiban (flat)

1. noun(air) bubble (esp. in a liquid)

• Synonym泡あわNeutralEveryday word for bubbles and foam, single or in a mass — beer head, soap suds. 「気泡」 is the more technical term for air trapped inside a liquid or solid.
• SynonymバブルNeutralLoanword for bubbles, but mostly means the bubble economy, as in 「バブル崩壊」. For actual bubbles, 「気泡」 or 「泡」 is the usual choice.
• Related水泡すいほうWrittenWritten-style word for foam on the water; mostly figurative, as in 「水泡に帰す」 (come to nothing). Rarely used for actual bubbles.
• Related泡沫うたかたWrittenRead うたかた. Literary word for foam on the water, evoking the transience of life. 「気泡」 is a plain, physical term.
• Related水の泡みずのあわNeutralIdiom for efforts coming to nothing, as in 「水の泡になる」. For actual bubbles, use 「気泡」 or 「泡」.

Use 「気泡」 for air bubbles inside a liquid or glass, as in 「ガラスの気泡」. Everyday bubbles are 「泡」; the bubble economy is 「バブル」; efforts coming to nothing are 「水の泡」. 「水泡」 and 「泡沫」 are literary.

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

1. 液体えきたい、固体こたいの中なかの空気くうきを含ふくむ泡あわ。