laver

The word 'laver' entered English in the 14th century via Old French laveoir, which itself descended from the Latin lavātōrium, a noun derived from lavāre ("to wash"). The core Latin root lav- can be traced further back to the Proto-Indo-European root lewh₃-, meaning "to wash". The literal logic of the morphemes is transparent: the instrument (-er) for washing (lav-). This meaning is preserved in its primary definition as a ceremonial washbasin. The secondary meaning, referring to an edible seaweed, arose in the 17th century from its use in Welsh coastal areas, where the plant was gathered and washed in fresh water before eating, thus creating a semantic link through the act of cleansing.

Structure: lav (wash) + er (agent/instrument suffix) - lav: From Latin lavāre, meaning "to wash". Its functional role is the core semantic root. - er: An English agent or instrument noun-forming suffix, from Old English -ere, indicating "a thing used for" the action.