真空(kong)(kong)(kong)，這一(yi)(yi)術語譯自拉丁(ding)文vacuo，其(qi)意義是虛無(wu)。其(qi)實真空(kong)(kong)(kong)應(ying)理解(jie)為(wei)氣(qi)體(ti)較(jiao)稀薄的空(kong)(kong)(kong)間(jian)。在(zai)指定的空(kong)(kong)(kong)間(jian)內(nei)，低于(yu)一(yi)(yi)個(ge)大氣(qi)壓力(li)的氣(qi)體(ti)狀態(tai)(tai)統稱(cheng)為(wei)真空(kong)(kong)(kong)。真空(kong)(kong)(kong)狀態(tai)(tai)下(xia)氣(qi)體(ti)稀薄程度稱(cheng)為(wei)真空(kong)(kong)(kong)度（degreeofvacuum），通(tong)常用壓力(li)值表示(shi)。因此真空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)實際上不是完全真空(kong)(kong)(kong)的，采用真空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)技(ji)術包(bao)(bao)裝(zhuang)(zhuang)的食品容器內(nei)的真空(kong)(kong)(kong)度通(tong)常在(zai)600-1333Pa。所(suo)以，又將(jiang)真空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)稱(cheng)為(wei)減壓包(bao)(bao)裝(zhuang)(zhuang)或排氣(qi)包(bao)(bao)裝(zhuang)(zhuang)。