真(zhen)空(kong)(kong)，這(zhe)一(yi)術(shu)語譯自拉丁文vacuo，其(qi)意義是虛無。其(qi)實(shi)真(zhen)空(kong)(kong)應理解(jie)為氣(qi)(qi)體(ti)較(jiao)稀(xi)(xi)薄(bo)的(de)空(kong)(kong)間(jian)。在指定(ding)的(de)空(kong)(kong)間(jian)內(nei)，低(di)于(yu)一(yi)個大氣(qi)(qi)壓力(li)的(de)氣(qi)(qi)體(ti)狀態統稱為真(zhen)空(kong)(kong)。真(zhen)空(kong)(kong)狀態下氣(qi)(qi)體(ti)稀(xi)(xi)薄(bo)程(cheng)度(du)稱為真(zhen)空(kong)(kong)度(du)（degreeofvacuum），通(tong)常用(yong)壓力(li)值表示。因此真(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(shu)包(bao)裝(zhuang)的(de)食品容(rong)器內(nei)的(de)真(zhen)空(kong)(kong)度(du)通(tong)常在600-1333Pa。所以(yi)，又將真(zhen)空(kong)(kong)包(bao)裝(zhuang)稱為減壓包(bao)裝(zhuang)或排氣(qi)(qi)包(bao)裝(zhuang)。