[1905–10; geo- + hydrology]This word is first recorded in the period 1905–10. Other words that entered Englishat around the same time include: cadre, one-shot, revolving door, scrounge, thiaminegeo- is a combining form meaning “the earth,” used in the formation of compound words.Other words that use the affix geo- include: geocentric, geofact, geognosy, geostationary, geosyncline