A "disability" is some kind of problem with a person's body such as:

• blindness
• deafness
• a missing arm or leg
• a mental disability

A person who has one of these problems is called "disabled"

If you want to be very careful not to offend someone with one of these problems, you might use the term "differently abled" instead of "disabled". However, not everyone accepts this term because some people think that it's silly to be so careful about what we call people in this group.