in Roman antiquity, a place where the gladiators fought; so called from its being always strewed with sand, to conceal from the view of the people the blood spilt in the combat. Nero is said to have strewed the arena with gold dust.

ARENARIA, or Sandwort, in botany: A genus of the decandria trigynia clas; and in the natural method ranking under the 22d order, Caryophyllae. The calyx has five open leaves; the petals are five, and entire; the capsule is unilocular, and contains many seeds. There are 17 species of arenaria, only seven of which are natives of Britain, viz. the peplodes, or sea-sandwort; the trinervis, or plautain-leaved sandwort; the serpylli-folia, or leafy sandwort; the saxatilis, or mountain-sandwort; the laricifolia, or larchleaved sandwort; the tenuifolia, or fine-leaved sandwort; and the rubra, or purple-flowered sandwort.