(n.) The iterative sound of beating a drum, or of a galloping horse.

aim at antiaircraft barrage arch dam backstop bamboo curtain bank bar barrier bear-trap dam beat beating beaver dam blast blitz bombard bombardment boom box barrage breakwater breastwork brick wall broadside buffer bulkhead bulwark burst cannon cannonade cannonry cofferdam commence firing creeping barrage dam defense dike ditch drum drum music drumbeat drumfire drumming earthwork embankment emergency barrage enfilade eruption fence fire a volley fire at fire upon flare flutter fusillade gate gravity dam groin hail hydraulic-fill dam iron curtain jam jetty leaping weir levee logjam milldam moat mole mortar mortar barrage mound normal barrage open fire open up on outburst palpitation paradiddle parapet patter pepper pitapat pitter-patter pop at portcullis pound pounding pulsation rake rampart rat-a-tat rat-tat rat-tat-tat rataplan rattattoo roadblock rock-fill dam roll rub-a-dub ruff ruffle salvo seawall shell shoot shoot at shower shutter dam snipe snipe at spatter splutter spray sputter staccato standing barrage stone wall storm strafe stream surge take aim at tat-tat tattoo throb throbbing thrum thumping tom-tom tornado torpedo volley wall weir wicket dam work zero in on