真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)，這(zhe)一(yi)術語譯自拉丁文vacuo，其(qi)意義(yi)是虛無。其(qi)實真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)應(ying)理解為(wei)(wei)氣體(ti)較稀薄的(de)空(kong)(kong)(kong)(kong)(kong)間。在指(zhi)定的(de)空(kong)(kong)(kong)(kong)(kong)間內，低于一(yi)個大氣壓(ya)力的(de)氣體(ti)狀(zhuang)態統稱為(wei)(wei)真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)。真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)狀(zhuang)態下氣體(ti)稀薄程度(du)稱為(wei)(wei)真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)度(du)（degreeofvacuum），通(tong)常用(yong)壓(ya)力值表示。因此(ci)真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)包(bao)(bao)裝實際上(shang)不是完全真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)的(de)，采用(yong)真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)包(bao)(bao)裝技術包(bao)(bao)裝的(de)食品容器內的(de)真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)度(du)通(tong)常在600-1333Pa。所以，又將真(zhen)(zhen)空(kong)(kong)(kong)(kong)(kong)包(bao)(bao)裝稱為(wei)(wei)減壓(ya)包(bao)(bao)裝或排氣包(bao)(bao)裝。