Capital assets are long-term assets, also known as fixed assets.
These terms are interchangeable. Assets are generally divided into short-term and long-term assets, the distinction depending on how long they last.
Usually the difference between short term and long term is a matter of accounting and financial policy. Five years is probably the most frequent division point, meaning that assets that depreciate over more than five years are long-term assets. Ten years and three years are also common.