真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)，這一術語(yu)譯自拉丁文vacuo，其(qi)意義是(shi)虛無(wu)。其(qi)實真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)應理解(jie)為氣(qi)體較稀薄(bo)的(de)(de)(de)空(kong)(kong)(kong)間(jian)。在指(zhi)定的(de)(de)(de)空(kong)(kong)(kong)間(jian)內，低(di)于(yu)一個大氣(qi)壓力的(de)(de)(de)氣(qi)體狀(zhuang)態統稱(cheng)為真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)。真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)狀(zhuang)態下(xia)氣(qi)體稀薄(bo)程度稱(cheng)為真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)度（degreeofvacuum），通常用(yong)壓力值表(biao)示。因此真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)(bao)裝實際(ji)上不是(shi)完全真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)的(de)(de)(de)，采用(yong)真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)(bao)裝技術包(bao)(bao)(bao)裝的(de)(de)(de)食品(pin)容器內的(de)(de)(de)真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)度通常在600-1333Pa。所以(yi)，又將真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)(bao)裝稱(cheng)為減壓包(bao)(bao)(bao)裝或排氣(qi)包(bao)(bao)(bao)裝。