A laver. 1. A vessel for washing; a large basin. 2. One who laves; a washer. 3. The fronds of certain marine algae used as food, and for making a sauce called laver sauce. Green laver is the Ulva latissima; purlpe laver, Porphyra laciniata and P. vulgaris. It is prepared by stewing, either alone or with other vegetables, and with various condiments; -- called also sloke, or sloakan.