Never.

plural of no-lone zone

On a traffic sign, indicates that parking a vehicle is not allowed within the area of influence of the sign.

plural of no-fly zone

Alternative form of like a chicken with its head cut off

beneficial actions often go unappreciated or are met with outright hostility.

Beneficial actions often go unappreciated or are met with outright hostility or demands for further work.

The owner of a work, or other copyright holder, releases the work into public domain.

(informal, often sarcastic, often offensive) Used immediately before or after a statement to indicate that there was no homosexual meaning intended, especially when such a meaning is a reasonable interpretation.

A theorem postulating that all black hole solutions of the Einstein-Maxwell equations in general relativity can be completely characterized by only three externally observable classical parameters: mass, electric charge, and angular momentum.