-sē, -si noun
( -es )
Etymology: alteration (influenced by Latin hydromantia ) of Middle English ydromancye, from Middle French ydromancie, from Latin hydromantia, from (assumed) Greek hydromanteia, from Greek hydr- + manteia divination — more at -mancy
: divination by water or other liquid (as by visions seen therein or the ebb and flow of tides)