Webster’s Revised Unabridged Dictionary · 1913
Montre
Mon′tre, n. [F., show, show case, organ case.] 1. (Organ Building) A stop, usually the open diapason, having its pipes "shown" as part of the organ case, or otherwise specially mounted.
2. A hole in the wall of a pottery kiln, by which the state of the pieces within can be judged.