enormous thing
Archaic noun for something huge or colossal. Not used in modern Japanese.
In old texts, 天山 is sometimes used as a metaphor for something enormous.
Archaic adverbial use meaning 'greatly' or 'very'. Rare and obsolete.
In classical language, 天山 can express a high degree, as in 天山驚く (greatly surprised).
The reading あめやま is an archaic Japanese reading of the kanji 天山, literally 'heaven mountain'. The exact historical derivation is uncertain; it may be a poetic or metaphorical usage from classical literature.