真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)，這(zhe)一術語譯自拉丁文vacuo，其意(yi)義(yi)是虛無。其實(shi)真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)應理解(jie)為氣體(ti)較稀薄的(de)空(kong)(kong)(kong)間。在(zai)指定的(de)空(kong)(kong)(kong)間內，低于一個大氣壓(ya)力的(de)氣體(ti)狀態(tai)統稱為真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)。真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)狀態(tai)下氣體(ti)稀薄程度稱為真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)度（degreeofvacuum），通常用壓(ya)力值表示。因此真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)(bao)裝實(shi)際上不(bu)是完全(quan)真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)的(de)，采用真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)(bao)裝技(ji)術包(bao)(bao)(bao)裝的(de)食品(pin)容器內的(de)真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)度通常在(zai)600-1333Pa。所以，又將真(zhen)(zhen)(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)(bao)裝稱為減壓(ya)包(bao)(bao)(bao)裝或排氣包(bao)(bao)(bao)裝。