?双丁槽焊    double-J groove weld

?双极开关    double-pole switch

?加力板,加强板,二重板    doubler

?加力板,加强板,二重板    doubling plate (or doubler)

?和面器    dough mixer

?鸠尾    dovetail

?鸠尾接合    dovetail joint

?鸠尾榫眼    dovetail mortise

?鸠尾[形]板    dovetail plate

?鸠尾榫舌    dovetail tongue

?深海作业艇    DOWB (= deep ocean work boat)

?定位销,合钉,双尖钉    dowel

?定位销,合钉    dowel pin

?销合    doweling

?降水管(锅炉)    down cast (or comer)

?进排气通风筒    down cast and up-take ventilator

?降流管集箱,降流管头箱    down cast header

?进气通风筒    down cast ventilator

?下向焊[接]    down hand welding

?下坡焊[接]    down hill direction welding

?下行冲程    down stroke

?下溜    down wash

?俯焊,平焊    down welding

?降水管,降流管    downcast pipe (or downcomer)

?降水管(锅炉)    down-comer tube

?降水管    down-comer tube

?下坡度与上坡度    down-grade and up-grade

?下拉索    downhaul

?飞轮泵    downton pump

?下向通风器    downward ventilator

?吃水计,通风压力计    draft gauge

?通风落差    draft head (or height)

?通风损失    draft loss

?吃水标    draft mark

?吃水标尺    draft scale

?送风道    draft trunk

?绘图    drafting

?绘图员    draftsman

?拖锚    drag anchor

?制动链    drag chain

?制动链(下水)    drag chain

?曳力系数    drag coefficient