真(zhen)空(kong)(kong)，這一術(shu)語譯自拉(la)丁(ding)文(wen)vacuo，其意義是虛無。其實真(zhen)空(kong)(kong)應(ying)理(li)解(jie)為(wei)(wei)氣體較稀薄的(de)空(kong)(kong)間。在(zai)指(zhi)定的(de)空(kong)(kong)間內，低于一個大(da)氣壓(ya)力(li)的(de)氣體狀態統稱(cheng)為(wei)(wei)真(zhen)空(kong)(kong)。真(zhen)空(kong)(kong)狀態下氣體稀薄程度(du)稱(cheng)為(wei)(wei)真(zhen)空(kong)(kong)度(du)（degreeofvacuum），通常用(yong)壓(ya)力(li)值表示。因此真(zhen)空(kong)(kong)包(bao)(bao)裝(zhuang)實際(ji)上不(bu)是完全真(zhen)空(kong)(kong)的(de)，采(cai)用(yong)真(zhen)空(kong)(kong)包(bao)(bao)裝(zhuang)技(ji)術(shu)包(bao)(bao)裝(zhuang)的(de)食品容器(qi)內的(de)真(zhen)空(kong)(kong)度(du)通常在(zai)600-1333Pa。所以，又將真(zhen)空(kong)(kong)包(bao)(bao)裝(zhuang)稱(cheng)為(wei)(wei)減壓(ya)包(bao)(bao)裝(zhuang)或排氣包(bao)(bao)裝(zhuang)。