真(zhen)空(kong)(kong)(kong)，這一術語譯自拉丁文vacuo，其意義是虛無。其實真(zhen)空(kong)(kong)(kong)應(ying)理解(jie)為(wei)(wei)氣(qi)體(ti)較稀(xi)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(li)的(de)(de)氣(qi)體(ti)狀(zhuang)態統稱為(wei)(wei)真(zhen)空(kong)(kong)(kong)。真(zhen)空(kong)(kong)(kong)狀(zhuang)態下氣(qi)體(ti)稀(xi)薄程度(du)(du)稱為(wei)(wei)真(zhen)空(kong)(kong)(kong)度(du)(du)（degreeofvacuum），通常用壓力(li)值表示。因此(ci)真(zhen)空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)實際上不是完(wan)全(quan)真(zhen)空(kong)(kong)(kong)的(de)(de)，采用真(zhen)空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)技術包(bao)(bao)裝(zhuang)(zhuang)的(de)(de)食品容器內的(de)(de)真(zhen)空(kong)(kong)(kong)度(du)(du)通常在600-1333Pa。所(suo)以(yi)，又將(jiang)真(zhen)空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)稱為(wei)(wei)減壓包(bao)(bao)裝(zhuang)(zhuang)或(huo)排氣(qi)包(bao)(bao)裝(zhuang)(zhuang)。