真(zhen)空(kong)(kong)，這一術(shu)語譯自拉丁文vacuo，其意義是虛無(wu)。其實(shi)真(zhen)空(kong)(kong)應理解為氣(qi)(qi)體(ti)較稀薄的(de)(de)空(kong)(kong)間(jian)(jian)。在(zai)指定的(de)(de)空(kong)(kong)間(jian)(jian)內(nei)，低于(yu)一個大氣(qi)(qi)壓(ya)力的(de)(de)氣(qi)(qi)體(ti)狀(zhuang)(zhuang)態統稱(cheng)為真(zhen)空(kong)(kong)。真(zhen)空(kong)(kong)狀(zhuang)(zhuang)態下氣(qi)(qi)體(ti)稀薄程(cheng)度稱(cheng)為真(zhen)空(kong)(kong)度（degreeofvacuum），通常用(yong)(yong)壓(ya)力值表示。因此真(zhen)空(kong)(kong)包(bao)(bao)(bao)裝(zhuang)實(shi)際(ji)上不是完全真(zhen)空(kong)(kong)的(de)(de)，采用(yong)(yong)真(zhen)空(kong)(kong)包(bao)(bao)(bao)裝(zhuang)技術(shu)包(bao)(bao)(bao)裝(zhuang)的(de)(de)食品容器內(nei)的(de)(de)真(zhen)空(kong)(kong)度通常在(zai)600-1333Pa。所以，又將真(zhen)空(kong)(kong)包(bao)(bao)(bao)裝(zhuang)稱(cheng)為減壓(ya)包(bao)(bao)(bao)裝(zhuang)或排氣(qi)(qi)包(bao)(bao)(bao)裝(zhuang)。