ology

The suffix -ology comes from the Greek word logos, which can mean "word," "reason," or "study." In English, it developed into an ending used for the systematic study of a subject. It usually points to more than simple interest. When a word ends in -ology, it often names a recognized area of learning or a serious subject of study.

You will see -ology in many academic and professional words. Cardiology is the study of the heart, dermatology is the study of the skin, and geology is the study of the Earth. But it is not limited to the natural sciences. There is also demonology, which deals with demons in religion or folklore, and numerology, which refers to a belief system about the hidden meaning of numbers rather than a science.

One useful thing about -ology is how flexible it is. It can join many different roots to name a specific subject area. Some -ology words refer to well-established fields, while others are rare, informal, or tied to beliefs that are not scientific. Even so, the ending usually tells you that the word is about a subject being studied in an organized way. So when you hear a word ending in -ology, you can usually understand it as pointing to the study of something.