Definitions

1. noun

A short or informal name for a computer operating system, especially one from Apple.

“She updated the os on her laptop.”

2. noun

A prefix used in the names of biological species to denote ‘jaw’ or ‘mouth’, especially in the names of molluscs such as oysters and octopuses.

“The os of the oyster is a bivalve mollusc.”

3. noun

In anatomy, a part of the pelvis that forms the socket of the hip joint.

“The os pubis is a part of the pelvis.”

4. noun

The os, or osseous, part of the eye, specifically the sclera and cornea.

“The os of the eye is the white part.”

5. noun

A small opening or hole, especially in a shell or pod.

“The os of the seed pod helps it release the seeds.”