真空(kong)(kong)(kong)，這(zhe)一(yi)術語譯(yi)自(zi)拉(la)丁文(wen)vacuo，其意義是(shi)虛無。其實(shi)(shi)真空(kong)(kong)(kong)應理(li)解為氣(qi)體(ti)較(jiao)稀(xi)薄的(de)空(kong)(kong)(kong)間。在(zai)指定(ding)的(de)空(kong)(kong)(kong)間內，低于一(yi)個大氣(qi)壓力(li)(li)的(de)氣(qi)體(ti)狀態統稱(cheng)(cheng)為真空(kong)(kong)(kong)。真空(kong)(kong)(kong)狀態下氣(qi)體(ti)稀(xi)薄程度(du)(du)稱(cheng)(cheng)為真空(kong)(kong)(kong)度(du)(du)（degreeofvacuum），通常用(yong)壓力(li)(li)值表示。因此真空(kong)(kong)(kong)包(bao)裝(zhuang)實(shi)(shi)際上不(bu)是(shi)完(wan)全真空(kong)(kong)(kong)的(de)，采用(yong)真空(kong)(kong)(kong)包(bao)裝(zhuang)技術包(bao)裝(zhuang)的(de)食(shi)品容器內的(de)真空(kong)(kong)(kong)度(du)(du)通常在(zai)600-1333Pa。所以(yi)，又將真空(kong)(kong)(kong)包(bao)裝(zhuang)稱(cheng)(cheng)為減壓包(bao)裝(zhuang)或排氣(qi)包(bao)裝(zhuang)。