真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)，這一術語譯自(zi)拉丁(ding)文(wen)vacuo，其(qi)意(yi)義是虛無(wu)。其(qi)實(shi)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)應(ying)理解為氣(qi)體較稀(xi)(xi)薄的空(kong)(kong)(kong)(kong)間。在(zai)指(zhi)定的空(kong)(kong)(kong)(kong)間內(nei)，低于一個大氣(qi)壓(ya)力(li)的氣(qi)體狀(zhuang)態統稱為真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)。真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)狀(zhuang)態下氣(qi)體稀(xi)(xi)薄程(cheng)度(du)稱為真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)度(du)（degreeofvacuum），通(tong)常用壓(ya)力(li)值表示(shi)。因此真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)包裝(zhuang)(zhuang)實(shi)際上不是完全(quan)真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)的，采用真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)包裝(zhuang)(zhuang)技術包裝(zhuang)(zhuang)的食品容器內(nei)的真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)度(du)通(tong)常在(zai)600-1333Pa。所以(yi)，又將真(zhen)(zhen)(zhen)空(kong)(kong)(kong)(kong)包裝(zhuang)(zhuang)稱為減(jian)壓(ya)包裝(zhuang)(zhuang)或排(pai)氣(qi)包裝(zhuang)(zhuang)。