chain latch

plural chain latches

1. A door chain.First known use late 19ᵗʰ century

   Dov slipped the chain latch into place and opened the door a crack.

   1958, Leon Uris, chapter 14, in Exodus, page 429

   2 more examples

   [Mitral stenosis] is apparently due to the sudden tension on the edges of the mitral valve when, with ventricular diastole, it starts to open widely but cannot. It may well be compared to the opening of a door protected by a chain latch;

   1917, Austin Flint and Henry C. Thacher, A Manual of Physical Diagnosis, 7th edition, page 332

   The door opened, but only a little bit. Harris didn’t take off the chain latch, and Rhodes could see only a bit of his face through the opening.

   2013, Bill Crider, chapter 16, in Compound Murder, page 176