真空(kong)(kong)(kong)(kong)，這一術語譯自拉丁(ding)文vacuo，其意義是虛無。其實(shi)(shi)真空(kong)(kong)(kong)(kong)應(ying)理解為氣(qi)體較稀(xi)(xi)薄的空(kong)(kong)(kong)(kong)間。在(zai)指定的空(kong)(kong)(kong)(kong)間內，低于(yu)一個大氣(qi)壓(ya)力的氣(qi)體狀(zhuang)態(tai)統稱為真空(kong)(kong)(kong)(kong)。真空(kong)(kong)(kong)(kong)狀(zhuang)態(tai)下氣(qi)體稀(xi)(xi)薄程度稱為真空(kong)(kong)(kong)(kong)度（degreeofvacuum），通(tong)常(chang)用壓(ya)力值表示。因(yin)此真空(kong)(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)實(shi)(shi)際上不是完全真空(kong)(kong)(kong)(kong)的，采用真空(kong)(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)技術包(bao)(bao)裝(zhuang)(zhuang)的食品容器內的真空(kong)(kong)(kong)(kong)度通(tong)常(chang)在(zai)600-1333Pa。所以，又將真空(kong)(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)稱為減壓(ya)包(bao)(bao)裝(zhuang)(zhuang)或排氣(qi)包(bao)(bao)裝(zhuang)(zhuang)。