Thĕr’mo-stāt, n.

n. [Fr. thermostat, from Gr. θέρμη, heat, θερμός, hot, and ἱστάναι, to make to stand, to set.] A self-acting apparatus for regulating temperature by the unequal expansion of different metals by heat, as in opening or closing the draught of a stove, and the like, as the heat becomes greater or less than is desired.