真(zhen)空(kong)(kong)，這一術語譯自拉丁文vacuo，其意義是虛(xu)無。其實(shi)真(zhen)空(kong)(kong)應理(li)解為(wei)(wei)氣體(ti)較(jiao)稀(xi)薄的(de)空(kong)(kong)間。在(zai)指定的(de)空(kong)(kong)間內(nei)，低于一個大氣壓力的(de)氣體(ti)狀態統稱為(wei)(wei)真(zhen)空(kong)(kong)。真(zhen)空(kong)(kong)狀態下(xia)氣體(ti)稀(xi)薄程度稱為(wei)(wei)真(zhen)空(kong)(kong)度（degreeofvacuum），通(tong)常用(yong)壓力值表示。因(yin)此真(zhen)空(kong)(kong)包(bao)裝(zhuang)實(shi)際上不是完全真(zhen)空(kong)(kong)的(de)，采用(yong)真(zhen)空(kong)(kong)包(bao)裝(zhuang)技術包(bao)裝(zhuang)的(de)食品(pin)容器(qi)內(nei)的(de)真(zhen)空(kong)(kong)度通(tong)常在(zai)600-1333Pa。所以，又將真(zhen)空(kong)(kong)包(bao)裝(zhuang)稱為(wei)(wei)減壓包(bao)裝(zhuang)或排氣包(bao)裝(zhuang)。