真(zhen)(zhen)空(kong)(kong)，這(zhe)一(yi)術語譯自(zi)拉丁文vacuo，其(qi)意義(yi)是虛無。其(qi)實(shi)(shi)真(zhen)(zhen)空(kong)(kong)應(ying)理解為(wei)(wei)氣體(ti)較稀薄(bo)的(de)(de)空(kong)(kong)間(jian)(jian)。在指定(ding)的(de)(de)空(kong)(kong)間(jian)(jian)內，低于一(yi)個大氣壓力(li)的(de)(de)氣體(ti)狀態統稱(cheng)為(wei)(wei)真(zhen)(zhen)空(kong)(kong)。真(zhen)(zhen)空(kong)(kong)狀態下(xia)氣體(ti)稀薄(bo)程度稱(cheng)為(wei)(wei)真(zhen)(zhen)空(kong)(kong)度（degreeofvacuum），通(tong)常用壓力(li)值表示。因此真(zhen)(zhen)空(kong)(kong)包裝實(shi)(shi)際上不是完全真(zhen)(zhen)空(kong)(kong)的(de)(de)，采用真(zhen)(zhen)空(kong)(kong)包裝技術包裝的(de)(de)食品容器內的(de)(de)真(zhen)(zhen)空(kong)(kong)度通(tong)常在600-1333Pa。所以，又將真(zhen)(zhen)空(kong)(kong)包裝稱(cheng)為(wei)(wei)減壓包裝或排氣包裝。