exercise
n. C / Un. physical activity you do to stay healthy or get stronger. It can also mean a task you do to practice a skill, like a math problem.
n. physical activity performed to improve health or fitness; alternatively, a specific task or set of tasks designed to develop a skill. Both countable and uncountable depending on whether it refers to a specific drill or the general concept of activity.
I try to get some exercise every morning.
The doctor recommended regular exercise and a balanced diet to help lower his blood pressure.
While the physical benefits of exercise are well-documented, recent studies emphasize its role in cognitive maintenance and the reduction of stress hormones in the bloodstream.
From Middle English exercise, from Old French exercise, from Latin exercitium.
Uncountable when referring to the general concept of physical activity; countable when referring to specific tasks in a textbook or a particular set of movements.
I did many exercises at the gymI did a lot of exercise at the gymWhen referring to general physical activity for health, the word is usually uncountable. 'Exercises' usually refers to specific school tasks or distinct physical movements like push-ups.