Geological means to do with the earth's rocks and their history. A geological survey.
Geological time is the phrase most people meet, and it means millions of years rather than thousands. A geological map shows what is under the soil rather than what is on it.
1adjectivegeologicalTo do with the earth's rocks and their history.
“The geological survey found coal under half the parish.”
geological is a quality.
Geo-, from Greek ge, the earth, plus logia, study, with the adjective attested slightly before geology itself.
From geōlogia + ical; first attested slightly earlier than geology. by surface analysis, geo- + -logical.
Etymology from Wiktionary, CC BY-SA