(a) An upright enclosing structure, usu. constructed of stone or brick, serving to bound and defend a city or castle; also in fig. context (b) the flat top of a city wall as a surface for……

(a) To be in motion, esp. back and forth or up and down, shake, flutter, swing; also fig. with ref. to (e) [quots. a1387 & a1425]; of teeth: be loose; of a boat: rock with the waves; of flesh: wobble……