岳 in classical Chinese specifically meant a great sacred mountain. China's
五岳 (Five Sacred Mountains) include
泰山 (east),
华山 (west),
衡山 (south),
恒山 (north), and
嵩山 (center).
岳 also means 'father-in-law's family' in modern Chinese —
岳父 (father-in-law),
岳母 (mother-in-law).