真空(kong)(kong)(kong)(kong)，這(zhe)一術語譯自拉丁文vacuo，其意義是虛無。其實真空(kong)(kong)(kong)(kong)應(ying)理(li)解為氣(qi)體較稀薄的(de)空(kong)(kong)(kong)(kong)間。在(zai)指定(ding)的(de)空(kong)(kong)(kong)(kong)間內(nei)，低于一個(ge)大氣(qi)壓(ya)力的(de)氣(qi)體狀態(tai)統(tong)稱(cheng)為真空(kong)(kong)(kong)(kong)。真空(kong)(kong)(kong)(kong)狀態(tai)下氣(qi)體稀薄程度(du)稱(cheng)為真空(kong)(kong)(kong)(kong)度(du)（degreeofvacuum），通常(chang)用壓(ya)力值表示。因此真空(kong)(kong)(kong)(kong)包(bao)裝(zhuang)實際(ji)上不是完(wan)全真空(kong)(kong)(kong)(kong)的(de)，采用真空(kong)(kong)(kong)(kong)包(bao)裝(zhuang)技術包(bao)裝(zhuang)的(de)食品容器內(nei)的(de)真空(kong)(kong)(kong)(kong)度(du)通常(chang)在(zai)600-1333Pa。所以，又將真空(kong)(kong)(kong)(kong)包(bao)裝(zhuang)稱(cheng)為減壓(ya)包(bao)裝(zhuang)或排氣(qi)包(bao)裝(zhuang)。