真(zhen)空(kong)(kong)(kong)(kong)，這(zhe)一(yi)術語譯自拉丁文vacuo，其意義(yi)是(shi)虛(xu)無。其實真(zhen)空(kong)(kong)(kong)(kong)應理解為氣(qi)體(ti)較稀薄的(de)(de)空(kong)(kong)(kong)(kong)間(jian)。在指定的(de)(de)空(kong)(kong)(kong)(kong)間(jian)內(nei)，低于一(yi)個大氣(qi)壓(ya)力的(de)(de)氣(qi)體(ti)狀(zhuang)(zhuang)態(tai)(tai)統稱(cheng)(cheng)為真(zhen)空(kong)(kong)(kong)(kong)。真(zhen)空(kong)(kong)(kong)(kong)狀(zhuang)(zhuang)態(tai)(tai)下氣(qi)體(ti)稀薄程(cheng)度稱(cheng)(cheng)為真(zhen)空(kong)(kong)(kong)(kong)度（degreeofvacuum），通常用壓(ya)力值表(biao)示。因此真(zhen)空(kong)(kong)(kong)(kong)包(bao)裝實際上(shang)不是(shi)完全真(zhen)空(kong)(kong)(kong)(kong)的(de)(de)，采用真(zhen)空(kong)(kong)(kong)(kong)包(bao)裝技術包(bao)裝的(de)(de)食(shi)品(pin)容器內(nei)的(de)(de)真(zhen)空(kong)(kong)(kong)(kong)度通常在600-1333Pa。所以，又將真(zhen)空(kong)(kong)(kong)(kong)包(bao)裝稱(cheng)(cheng)為減壓(ya)包(bao)裝或排氣(qi)包(bao)裝。