| a measuring instrument for measuring the angular distance between celestial objects; resembles an octant | any projection that is thought to resemble a human arm |
| a unit of angular distance equal to 60 degrees | the graduated arc that is attached to an instrument for measuring angles |
| | either of the two halves of a bow from handle to tip |
| | one of the jointed appendages of an animal used for locomotion or grasping: arm, leg, wing, flipper |
| | (astronomy) the circumferential edge of the apparent disc of the sun or the moon or a planet |
| | any of the main branches arising from the trunk or a bough of a tree |