真(zhen)空(kong)(kong)(kong)，這(zhe)一(yi)術語(yu)譯自拉丁文vacuo，其意義是(shi)虛無。其實真(zhen)空(kong)(kong)(kong)應理解(jie)為氣(qi)體較稀薄的(de)(de)空(kong)(kong)(kong)間。在(zai)指定的(de)(de)空(kong)(kong)(kong)間內(nei)，低于一(yi)個(ge)大氣(qi)壓力的(de)(de)氣(qi)體狀態(tai)(tai)統(tong)稱為真(zhen)空(kong)(kong)(kong)。真(zhen)空(kong)(kong)(kong)狀態(tai)(tai)下氣(qi)體稀薄程度(du)(du)稱為真(zhen)空(kong)(kong)(kong)度(du)(du)（degreeofvacuum），通常用(yong)壓力值(zhi)表示。因此真(zhen)空(kong)(kong)(kong)包(bao)裝(zhuang)(zhuang)實際(ji)上不(bu)是(shi)完全真(zhen)空(kong)(kong)(kong)的(de)(de)，采用(yong)真(zhen)空(kong)(kong)(kong)包(bao)裝(zhuang)(zhuang)技術包(bao)裝(zhuang)(zhuang)的(de)(de)食(shi)品容器內(nei)的(de)(de)真(zhen)空(kong)(kong)(kong)度(du)(du)通常在(zai)600-1333Pa。所以，又將(jiang)真(zhen)空(kong)(kong)(kong)包(bao)裝(zhuang)(zhuang)稱為減壓包(bao)裝(zhuang)(zhuang)或排氣(qi)包(bao)裝(zhuang)(zhuang)。