真(zhen)(zhen)空(kong)(kong)，這(zhe)一術語譯自拉丁文vacuo，其意義是虛(xu)無。其實真(zhen)(zhen)空(kong)(kong)應理解為(wei)氣體較稀(xi)薄(bo)的空(kong)(kong)間(jian)。在指定(ding)的空(kong)(kong)間(jian)內(nei)，低于一個大(da)氣壓(ya)力的氣體狀態(tai)統稱為(wei)真(zhen)(zhen)空(kong)(kong)。真(zhen)(zhen)空(kong)(kong)狀態(tai)下氣體稀(xi)薄(bo)程度(du)稱為(wei)真(zhen)(zhen)空(kong)(kong)度(du)（degreeofvacuum），通常用(yong)壓(ya)力值表示。因此(ci)真(zhen)(zhen)空(kong)(kong)包(bao)裝實際上不是完全真(zhen)(zhen)空(kong)(kong)的，采(cai)用(yong)真(zhen)(zhen)空(kong)(kong)包(bao)裝技(ji)術包(bao)裝的食品容器(qi)內(nei)的真(zhen)(zhen)空(kong)(kong)度(du)通常在600-1333Pa。所以，又將(jiang)真(zhen)(zhen)空(kong)(kong)包(bao)裝稱為(wei)減壓(ya)包(bao)裝或排氣包(bao)裝。