鎖具(ju)是(shi)指(zhi)起封(feng)閉作用(yong)(yong)(yong)(yong)的(de)器具(ju)，它包(bao)括鎖、鑰(yao)匙(chi)及其附(fu)件，一般(ban)解釋為“必須(xu)用(yong)(yong)(yong)(yong)鑰(yao)匙(chi)方(fang)能開脫的(de)封(feng)緘器”，現在(zai)，鎖具(ju)除(chu)用(yong)(yong)(yong)(yong)鑰(yao)匙(chi)開啟(qi)外，還可(ke)以用(yong)(yong)(yong)(yong)光(guang)、電、磁、聲及指(zhi)紋等指(zhi)令(ling)開啟(qi)。鎖具(ju)不單是(shi)防護用(yong)(yong)(yong)(yong)品，還具(ju)有“管理”和“裝飾”的(de)作用(yong)(yong)(yong)(yong)。在(zai)國(guo)際交往(wang)中也有一種禮儀，用(yong)(yong)(yong)(yong)贈送象征性的(de)“鑰(yao)匙(chi)”作為友誼的(de)表(biao)示。