late 18th cent. (in the general sense 'washing, a wash'): from French, from laver 'to wash'. la*va lamp n. a transparent electric lamp containing a viscous liquid in which a brightly colored waxy substance is suspended, rising and falling in irregular and constantly changing shapes. la*vash n. a Middle Eastern crisp flatbread. Armenian, from Turkish. lav*a*to*ri*al adj. of or relating to lavatories, in particular: - (of conversation or humor) characterized by undue reference to toilets and their use: the comic's lavatorial schoolboy humor. - resembling the style or