真空(kong)(kong)(kong)，這一(yi)術(shu)語譯自(zi)拉(la)丁文vacuo，其(qi)意義是虛無。其(qi)實真空(kong)(kong)(kong)應理解(jie)為(wei)氣體(ti)較稀(xi)薄的(de)空(kong)(kong)(kong)間。在(zai)指定(ding)的(de)空(kong)(kong)(kong)間內，低于(yu)一(yi)個大氣壓(ya)力(li)的(de)氣體(ti)狀(zhuang)態(tai)統稱(cheng)為(wei)真空(kong)(kong)(kong)。真空(kong)(kong)(kong)狀(zhuang)態(tai)下氣體(ti)稀(xi)薄程度稱(cheng)為(wei)真空(kong)(kong)(kong)度（degreeofvacuum），通常用壓(ya)力(li)值表示。因此真空(kong)(kong)(kong)包(bao)裝實際(ji)上不(bu)是完全真空(kong)(kong)(kong)的(de)，采用真空(kong)(kong)(kong)包(bao)裝技術(shu)包(bao)裝的(de)食品容(rong)器(qi)內的(de)真空(kong)(kong)(kong)度通常在(zai)600-1333Pa。所以，又將真空(kong)(kong)(kong)包(bao)裝稱(cheng)為(wei)減壓(ya)包(bao)裝或排氣包(bao)裝。