Scrabble?! ENVELOPE

Definitions of ENVELOPE in various dictionaries:

noun - a flat (usually rectangular) container for a letter, thin package, etc.

noun - any wrapper or covering

noun - a curve that is tangent to each of a family of curves

noun - a natural covering (as by a fluid)

noun - the maximum operating capability of a system (especially an aircraft)

noun - the bag containing the gas in a balloon

A flat, folded paper container, especially for a letter.

Something that envelops; a wrapping.

An enclosing structure or cover, such as a membrane or the outer coat of a virus.

The bag containing the gas in a balloon or an airship.

The set of limitations within which a technological system, especially an aircraft, can perform safely and effectively.

The coma of a comet.

A curve or surface that is tangent to every one of a family of curves or surfaces.

noun - a paper container