hydrothermal

/HH AY0 D R OW0 TH ER1 M AH0 L/
adjective
  1. 1

    Of, or relating to hot water.

  2. 2

    Of or relating to emanations of hot water that are rich in minerals, or to the rocks formed from them.

Source: https://en.wiktionary.org/wiki/hydrothermal