envelope
//ˈɛnvə(ˌ)ləʊp//
Forms
- Plural
- envelopes
Definitions
1.A paper or cardboard wrapper used to enclose small, flat items, especially letters, for mailing.
- I didn't know what was in the envelope.
2.Something that envelops; a wrapping.
- I didn't know what was in the envelope.
3.A bag containing the lifting gas of a balloon or airship; fabric that encloses the gas-bags of an airship.
- I didn't know what was in the envelope.
4.A mathematical curve, surface, or higher-dimensional object that is the tangent to a given family of lines, curves, surfaces, or higher-dimensional objects.
- I didn't know what was in the envelope.
Frequency
Overall
Rare· #4653
By learning goal
- Everyday conversation
- Rare
- General reading & writing
- Rare
- Academic
- Rare
- Literature
- Rare
Etymology
PIE word
*h₁én
From French enveloppe. The engineering sense is derived from flight envelope. The verb is from the noun.