蓋|ふたfuta[0]heiban (flat)

1. nouncover; lid; cap
   このふたはあのジャーのふただ。↗

   This lid belongs with that jar.

• Synonym上蓋うわぶたNeutralA removable lid on the top of a box or container. Narrower in range than 「蓋」, which is a general term for lids of all kinds, so this sounds more specific.
• RelatedキャップNeutralA loanword for caps that fit over an opening, such as bottle and pen caps; it also means a hat. A bottle cap can also be called 「瓶の蓋」.
• Antonym底そこNeutralThe bottom of a container or object — the opposite of 「蓋」, which covers the top.

Use 「蓋」 for lids in general; bottle caps can also be 「瓶の蓋」. Say 「キャップ」 for bottle or pen caps, 「上蓋」 when stressing the top lid of a container, and 「底」 for the bottom, the opposite of a lid.

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

1. 入れ物いれものなどの口くちを覆おおうものの総称そうしょう。