envelope

Definition

• n. a flat (usually rectangular) container for a letter, thin package, etc.
• n. any wrapper or covering
• n. a curve that is tangent to each of a family of curves
• n. a natural covering (as by a fluid)

Word forms

Plural

envelopes

Example sentences

1. n.

   She placed the letter inside the envelope before mailing it.

2. n.

   The virus is contained within a protective envelope that helps it survive outside the body.