Wiktionary
octavation
n. 1 (context music English) (rfdef topic=music English) 2 (context rare English) (rfdef: English) 3 (context astrology rare English) (rfdef lang=en topic=astrology) 4 (context mathematics English) (l en conversion Conversion) (of the (l en expression) of a (l en number)) from (l en denary) to (l en octal) (l en notation).