(military) An order that weapons may only be fired at targets (especially aircraft or missiles) that are positively identified as hostile.

A channel in which the tide sets.

plural of tick box

Of, or relating to, both China and Tibet / (linguistics) Of the Sino-Tibetan languages, one of the major language families.

A bed mattress made from a coarse cotton material, or shoddy, and filled with (usually) straw. / Also used to refer to the empty mattress bag.

(informal) A small person. / (Britain, informal) A small fish, especially a stickleback.

(dated, electronics) A small coil in series with the anode of a vacuum tube and coupled to the grid to provide feedback.

(biology) An intercellular junction between epithelial cells whose membranes join together to form a virtually impermeable barrier to fluid.

plural of tight junction

A hard-bodied tick, Ixodes scapularis, of the eastern and northern Midwestern United States, one of four species of tick that is carrier of Lyme disease.