真(zhen)(zhen)空(kong)(kong)(kong)(kong)，這一術語譯自拉(la)丁文vacuo，其(qi)意義(yi)是虛無。其(qi)實真(zhen)(zhen)空(kong)(kong)(kong)(kong)應理解為氣(qi)體(ti)較稀(xi)薄的(de)(de)(de)空(kong)(kong)(kong)(kong)間。在指定的(de)(de)(de)空(kong)(kong)(kong)(kong)間內，低于一個大氣(qi)壓力的(de)(de)(de)氣(qi)體(ti)狀(zhuang)態統稱為真(zhen)(zhen)空(kong)(kong)(kong)(kong)。真(zhen)(zhen)空(kong)(kong)(kong)(kong)狀(zhuang)態下氣(qi)體(ti)稀(xi)薄程(cheng)度(du)稱為真(zhen)(zhen)空(kong)(kong)(kong)(kong)度(du)（degreeofvacuum），通常(chang)用壓力值表(biao)示。因此真(zhen)(zhen)空(kong)(kong)(kong)(kong)包(bao)(bao)裝實際上不是完全真(zhen)(zhen)空(kong)(kong)(kong)(kong)的(de)(de)(de)，采(cai)用真(zhen)(zhen)空(kong)(kong)(kong)(kong)包(bao)(bao)裝技術包(bao)(bao)裝的(de)(de)(de)食(shi)品容(rong)器內的(de)(de)(de)真(zhen)(zhen)空(kong)(kong)(kong)(kong)度(du)通常(chang)在600-1333Pa。所以，又將真(zhen)(zhen)空(kong)(kong)(kong)(kong)包(bao)(bao)裝稱為減壓包(bao)(bao)裝或排(pai)氣(qi)包(bao)(bao)裝。