The suffix -ology means “the study of” something. It comes from ancient Greek and gets attached to the end of words to create names for entire fields of knowledge. Biology is the study of living things. Geology is the study of rocks and the Earth. Zoology is the study of animals.

When you see a word ending in -ology, you know someone has devoted serious time to understanding that subject deeply. Scientists who study these fields are called specialists: a person who studies biology is a biologist, someone who studies geology is a geologist, and so on.

There are -ologies for almost everything you can imagine. Meteorology is the study of weather. Archaeology is the study of ancient civilizations through the objects they left behind. Psychology is the study of the mind and behavior. Some -ologies sound unusual: entomology is the study of insects.

Next time you hear a word ending in -ology, you'll know you're hearing about a whole universe of knowledge that someone, somewhere, has made their life's work.