真(zhen)(zhen)空(kong)(kong)(kong)(kong)，這一術語譯自拉丁文vacuo，其意義是(shi)虛無。其實真(zhen)(zhen)空(kong)(kong)(kong)(kong)應理解為(wei)(wei)氣(qi)體(ti)較稀薄(bo)的空(kong)(kong)(kong)(kong)間(jian)。在指定的空(kong)(kong)(kong)(kong)間(jian)內，低于一個大氣(qi)壓力的氣(qi)體(ti)狀態統稱(cheng)(cheng)為(wei)(wei)真(zhen)(zhen)空(kong)(kong)(kong)(kong)。真(zhen)(zhen)空(kong)(kong)(kong)(kong)狀態下氣(qi)體(ti)稀薄(bo)程度(du)稱(cheng)(cheng)為(wei)(wei)真(zhen)(zhen)空(kong)(kong)(kong)(kong)度(du)（degreeofvacuum），通(tong)常用壓力值表示。因(yin)此真(zhen)(zhen)空(kong)(kong)(kong)(kong)包裝(zhuang)(zhuang)(zhuang)實際(ji)上不是(shi)完全真(zhen)(zhen)空(kong)(kong)(kong)(kong)的，采用真(zhen)(zhen)空(kong)(kong)(kong)(kong)包裝(zhuang)(zhuang)(zhuang)技術包裝(zhuang)(zhuang)(zhuang)的食品容器內的真(zhen)(zhen)空(kong)(kong)(kong)(kong)度(du)通(tong)常在600-1333Pa。所以，又將真(zhen)(zhen)空(kong)(kong)(kong)(kong)包裝(zhuang)(zhuang)(zhuang)稱(cheng)(cheng)為(wei)(wei)減(jian)壓包裝(zhuang)(zhuang)(zhuang)或排氣(qi)包裝(zhuang)(zhuang)(zhuang)。