真空(kong)(kong)(kong)，這一(yi)術(shu)(shu)語譯自拉丁(ding)文vacuo，其(qi)意義是虛無。其(qi)實真空(kong)(kong)(kong)應理解(jie)為(wei)(wei)氣(qi)體較(jiao)稀薄(bo)(bo)的(de)(de)空(kong)(kong)(kong)間(jian)。在(zai)指(zhi)定的(de)(de)空(kong)(kong)(kong)間(jian)內，低(di)于(yu)一(yi)個大氣(qi)壓力(li)的(de)(de)氣(qi)體狀態統稱為(wei)(wei)真空(kong)(kong)(kong)。真空(kong)(kong)(kong)狀態下氣(qi)體稀薄(bo)(bo)程度(du)稱為(wei)(wei)真空(kong)(kong)(kong)度(du)（degreeofvacuum），通常用(yong)壓力(li)值表示。因此真空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)實際上不是完(wan)全真空(kong)(kong)(kong)的(de)(de)，采用(yong)真空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)技術(shu)(shu)包(bao)(bao)裝(zhuang)的(de)(de)食品容器內的(de)(de)真空(kong)(kong)(kong)度(du)通常在(zai)600-1333Pa。所以，又將(jiang)真空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)稱為(wei)(wei)減壓包(bao)(bao)裝(zhuang)或排氣(qi)包(bao)(bao)裝(zhuang)。