真(zhen)空(kong)(kong)(kong)，這一術語譯自(zi)拉丁文vacuo，其意(yi)義是虛無。其實真(zhen)空(kong)(kong)(kong)應(ying)理解為氣(qi)體(ti)較稀薄的(de)(de)空(kong)(kong)(kong)間。在指定的(de)(de)空(kong)(kong)(kong)間內，低于一個大氣(qi)壓力的(de)(de)氣(qi)體(ti)狀(zhuang)態(tai)統稱為真(zhen)空(kong)(kong)(kong)。真(zhen)空(kong)(kong)(kong)狀(zhuang)態(tai)下氣(qi)體(ti)稀薄程度(du)稱為真(zhen)空(kong)(kong)(kong)度(du)（degreeofvacuum），通常(chang)用壓力值表(biao)示。因此真(zhen)空(kong)(kong)(kong)包(bao)(bao)裝實際上不是完全真(zhen)空(kong)(kong)(kong)的(de)(de)，采用真(zhen)空(kong)(kong)(kong)包(bao)(bao)裝技(ji)術包(bao)(bao)裝的(de)(de)食品容器(qi)內的(de)(de)真(zhen)空(kong)(kong)(kong)度(du)通常(chang)在600-1333Pa。所以，又將真(zhen)空(kong)(kong)(kong)包(bao)(bao)裝稱為減壓包(bao)(bao)裝或排氣(qi)包(bao)(bao)裝。