真(zhen)(zhen)空(kong)(kong)(kong)，這(zhe)一(yi)術語譯(yi)自拉丁文vacuo，其意(yi)義是(shi)虛無。其實真(zhen)(zhen)空(kong)(kong)(kong)應理解為(wei)氣體(ti)較(jiao)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(yi)個大氣壓力的(de)(de)氣體(ti)狀(zhuang)態(tai)統稱為(wei)真(zhen)(zhen)空(kong)(kong)(kong)。真(zhen)(zhen)空(kong)(kong)(kong)狀(zhuang)態(tai)下氣體(ti)稀(xi)薄程度稱為(wei)真(zhen)(zhen)空(kong)(kong)(kong)度（degreeofvacuum），通常用壓力值表(biao)示(shi)。因(yin)此(ci)真(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)實際上(shang)不是(shi)完全真(zhen)(zhen)空(kong)(kong)(kong)的(de)(de)，采用真(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)技術包(bao)(bao)裝(zhuang)的(de)(de)食品容(rong)器內的(de)(de)真(zhen)(zhen)空(kong)(kong)(kong)度通常在600-1333Pa。所以，又將真(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)稱為(wei)減壓包(bao)(bao)裝(zhuang)或排氣包(bao)(bao)裝(zhuang)。