a substance, usually a liquid or a gas, used to reduce the temperature of a system below a specified value by conducting away the heat produced in the operation of the system, as the liquid in an automobile cooling system or the fluid that removes heat from the core of a nuclear reactor.
2.
a lubricant that dissipates the heat caused by friction.
a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.
a chattering or flighty, light-headed person.
an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.
a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.