真(zhen)(zhen)空(kong)(kong)，這(zhe)一術(shu)語譯自拉丁(ding)文(wen)vacuo，其意義是(shi)虛無(wu)。其實真(zhen)(zhen)空(kong)(kong)應理解為(wei)氣(qi)體較稀薄(bo)的(de)空(kong)(kong)間。在指定的(de)空(kong)(kong)間內(nei)，低于一個大氣(qi)壓力的(de)氣(qi)體狀(zhuang)(zhuang)態統稱(cheng)(cheng)為(wei)真(zhen)(zhen)空(kong)(kong)。真(zhen)(zhen)空(kong)(kong)狀(zhuang)(zhuang)態下氣(qi)體稀薄(bo)程度(du)稱(cheng)(cheng)為(wei)真(zhen)(zhen)空(kong)(kong)度(du)（degreeofvacuum），通常用壓力值表示。因此真(zhen)(zhen)空(kong)(kong)包(bao)(bao)(bao)裝實際上(shang)不是(shi)完全真(zhen)(zhen)空(kong)(kong)的(de)，采用真(zhen)(zhen)空(kong)(kong)包(bao)(bao)(bao)裝技術(shu)包(bao)(bao)(bao)裝的(de)食品容(rong)器內(nei)的(de)真(zhen)(zhen)空(kong)(kong)度(du)通常在600-1333Pa。所以，又將真(zhen)(zhen)空(kong)(kong)包(bao)(bao)(bao)裝稱(cheng)(cheng)為(wei)減壓包(bao)(bao)(bao)裝或排氣(qi)包(bao)(bao)(bao)裝。