inlet

n. 1. A passage by which an inclosed place may be entered; a place of ingress; entrance; especially, a narrow waterway leading into a harbor. [ 1913 Webster ]

Doors and windows, inlets of men and of light. Sir H. Wotton. [ 1913 Webster ]

2. A bay or recess, as in the shore of a sea, lake, or large river; a narrow strip of water running into the land or between islands. [ 1913 Webster ]

3. That which is let in or inlaid; an inserted material. [ 1913 Webster ]

☞ Inlet is also used adjectively, as in inlet pipe, inlet valve, etc. [ 1913 Webster ]