真(zhen)(zhen)空(kong)(kong)，這(zhe)一術(shu)語譯自拉(la)丁文vacuo，其意義(yi)是(shi)(shi)虛無。其實(shi)真(zhen)(zhen)空(kong)(kong)應理解(jie)為(wei)氣(qi)體(ti)較稀(xi)薄的(de)(de)(de)空(kong)(kong)間(jian)。在指定的(de)(de)(de)空(kong)(kong)間(jian)內，低于一個大(da)氣(qi)壓力的(de)(de)(de)氣(qi)體(ti)狀態(tai)統稱為(wei)真(zhen)(zhen)空(kong)(kong)。真(zhen)(zhen)空(kong)(kong)狀態(tai)下氣(qi)體(ti)稀(xi)薄程度稱為(wei)真(zhen)(zhen)空(kong)(kong)度（degreeofvacuum），通(tong)常用(yong)壓力值表示。因此真(zhen)(zhen)空(kong)(kong)包(bao)(bao)裝實(shi)際上不是(shi)(shi)完全真(zhen)(zhen)空(kong)(kong)的(de)(de)(de)，采(cai)用(yong)真(zhen)(zhen)空(kong)(kong)包(bao)(bao)裝技術(shu)包(bao)(bao)裝的(de)(de)(de)食品容器內的(de)(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(bao)(bao)裝稱為(wei)減(jian)壓包(bao)(bao)裝或排氣(qi)包(bao)(bao)裝。