真(zhen)(zhen)空(kong)(kong)，這一術語譯自拉丁文vacuo，其意義是虛無(wu)。其實(shi)真(zhen)(zhen)空(kong)(kong)應理解為(wei)氣體(ti)(ti)較稀薄的(de)空(kong)(kong)間。在(zai)指定的(de)空(kong)(kong)間內(nei)，低于一個大氣壓(ya)力的(de)氣體(ti)(ti)狀態(tai)統稱(cheng)為(wei)真(zhen)(zhen)空(kong)(kong)。真(zhen)(zhen)空(kong)(kong)狀態(tai)下氣體(ti)(ti)稀薄程度稱(cheng)為(wei)真(zhen)(zhen)空(kong)(kong)度（degreeofvacuum），通(tong)常用壓(ya)力值表示。因此真(zhen)(zhen)空(kong)(kong)包(bao)(bao)裝實(shi)際上不是完全真(zhen)(zhen)空(kong)(kong)的(de)，采用真(zhen)(zhen)空(kong)(kong)包(bao)(bao)裝技術包(bao)(bao)裝的(de)食品(pin)容(rong)器(qi)內(nei)的(de)真(zhen)(zhen)空(kong)(kong)度通(tong)常在(zai)600-1333Pa。所以，又將真(zhen)(zhen)空(kong)(kong)包(bao)(bao)裝稱(cheng)為(wei)減壓(ya)包(bao)(bao)裝或排氣包(bao)(bao)裝。