de·tent /dɪˈtɛnt/
-noun Machinery.
a mechanism that temporarily keeps one part in a certain position relative to that of another, and can be released by applying force to one of the parts.

[Origin: 1680-90; < F détente, OF destente, deriv. of destendre to relax, equiv. to des– dis- + tendre to stretch; see tender]


Mr Singh nodded, one of those extremely precise nods that make you suspect a person has has click-detents in his cervical vertebrae.

Source: Turn of the Cards, Victor Milán.