Usually means most of the time, or in most cases, but not always. If you usually walk to school, that means you walk most days, but maybe sometimes you get a ride or ride your bike. If it usually rains in April, that means rain is common that month, but you'll still have some sunny days.

The word helps us describe patterns without making absolute promises. Your friend who usually arrives on time might occasionally be late. A restaurant that usually has your favorite dessert might run out now and then. Understanding usually helps you set realistic expectations: you can count on something happening most of the time, but you shouldn't be shocked when it doesn't.

When someone says “I'm usually good at math,” they're being honest about their general ability while admitting they sometimes struggle. This makes usually more accurate and truthful than saying “always.”