真空(kong)(kong)(kong)，這一術語譯自拉丁文vacuo，其(qi)意義是虛無。其(qi)實(shi)真空(kong)(kong)(kong)應理(li)解為(wei)(wei)氣(qi)(qi)體較稀(xi)薄的(de)(de)空(kong)(kong)(kong)間。在(zai)指定(ding)的(de)(de)空(kong)(kong)(kong)間內，低于一個大氣(qi)(qi)壓(ya)力(li)的(de)(de)氣(qi)(qi)體狀態(tai)統稱(cheng)為(wei)(wei)真空(kong)(kong)(kong)。真空(kong)(kong)(kong)狀態(tai)下氣(qi)(qi)體稀(xi)薄程度(du)稱(cheng)為(wei)(wei)真空(kong)(kong)(kong)度(du)（degreeofvacuum），通常(chang)用壓(ya)力(li)值表示。因此真空(kong)(kong)(kong)包裝(zhuang)實(shi)際上(shang)不是完全(quan)真空(kong)(kong)(kong)的(de)(de)，采用真空(kong)(kong)(kong)包裝(zhuang)技術包裝(zhuang)的(de)(de)食品(pin)容器內的(de)(de)真空(kong)(kong)(kong)度(du)通常(chang)在(zai)600-1333Pa。所(suo)以，又將真空(kong)(kong)(kong)包裝(zhuang)稱(cheng)為(wei)(wei)減壓(ya)包裝(zhuang)或(huo)排氣(qi)(qi)包裝(zhuang)。