What does "purslane" mean?

Purslane: An annual plant (Portulaca oleracea), with fleshy, succulent, obovate leaves, sometimes used as a pot herb and for salads, garnishing, and pickling. Flowering purslane, or Great flowered purslane, the Portulaca grandiflora. See Portulaca. -- Purslane tree, a South African shrub (Portulacaria Afra) with many small opposite fleshy obovate leaves. -- Sea purslane, a seashore plant (Arenaria peploides) with crowded opposite fleshy leaves. -- Water purslane, an aquatic plant (Ludwiqia palustris) but slightly resembling purslane.