is defined, by Mr Locke, to be a faculty of the mind, whereby it keeps, or retains, those simple ideas it has once received, by sensation or reflection. See METAPHYSICS.

Retention is also used, in medicine, &c., for the state of contraction in the solids or vascular parts of the body, which makes them hold fast their proper contents. In this sense, retention is opposed to evacuation and excretion.

RETIARIUS, in antiquity, a kind of gladiators, thus denominated from the net which they made use of against their antagonists, who were called secutores, and sometimes murmilloes.

This net they carried under their buckler, and when opportunity served, cast it over the head of their antagonist, and in this condition killed him with a trident which they bore in the other hand.