Etymology 1

Noun

1. An organ that synthesizes a substance, such as hormones or breast milk, and releases it, often into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).
2. A secretory structure on the surface of an organ.

Noun

1. (mechanical) a compressable cylindrical case and its contents around a shaft where it passes through a barrier, intended to prevent the passage of a fluid past the barrier. Examples:

   a. used around a ship’s propeller shaft.

   b. used around a tap, valve or faucet.