Anything that's geologic has something to do with the structure of the Earth and the way it has changed over time.
Scientists who study geologic features — including rocks in the earth's crust, volcanoes, sandy beaches, and all the other non-living things that make up our planet — are called geologists. If you're interested in geologic formations like the long, pointy mineral deposits that grow in caves, stalagmites and stalactites, you might consider a geologic career path too! Geologic is from geology and its Greek roots geo, "earth," and -logia, "a science."