真(zhen)(zhen)(zhen)空(kong)(kong)(kong)，這一術語譯自(zi)拉(la)丁文vacuo，其意義是虛無。其實真(zhen)(zhen)(zhen)空(kong)(kong)(kong)應理解為(wei)氣(qi)體較稀薄(bo)的(de)空(kong)(kong)(kong)間。在指定(ding)的(de)空(kong)(kong)(kong)間內，低于一個大氣(qi)壓力的(de)氣(qi)體狀(zhuang)態統(tong)稱(cheng)為(wei)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)。真(zhen)(zhen)(zhen)空(kong)(kong)(kong)狀(zhuang)態下氣(qi)體稀薄(bo)程度(du)稱(cheng)為(wei)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)度(du)（degreeofvacuum），通常用(yong)(yong)壓力值表(biao)示。因此真(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)裝(zhuang)(zhuang)實際上(shang)不(bu)是完全真(zhen)(zhen)(zhen)空(kong)(kong)(kong)的(de)，采用(yong)(yong)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)裝(zhuang)(zhuang)技術包(bao)裝(zhuang)(zhuang)的(de)食(shi)品容器內的(de)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)度(du)通常在600-1333Pa。所以，又將真(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)裝(zhuang)(zhuang)稱(cheng)為(wei)減(jian)壓包(bao)裝(zhuang)(zhuang)或(huo)排氣(qi)包(bao)裝(zhuang)(zhuang)。