What is a old lady that has never married called?

An old lady who has never married is often referred to as a "spinster." This term historically carried connotations of being unmarried and of a certain age, typically implying a woman who has chosen to remain single, either by preference or circumstance. While the term can be considered outdated and carries a stigma, it may still be used in literary or historical contexts. In modern usage, terms like "single" or "unmarried" are more common and neutral.