Envelope
01
封筒, 包み
a thin, paper cover in which we put and send a letter
例
He wrote the address on the envelope.
彼は封筒に住所を書いた。
02
封筒, 包み
any wrapper or covering
03
封筒, ガス袋
the bag containing the gas in a balloon
04
エンベロープ, 運用限界
the maximum operating capability of a system (especially an aircraft)
05
包み, 被覆
a natural covering (as by a fluid)
06
包絡線, エンベロープ
a curve that is tangent to each of a family of curves
