1. A state of feeling sympathy or understanding towards another person; like-mindedness: Jack and Jill appeared to have a lot of compatibility in their marriage, but Bill and Patty didn't get along with each other and separated within a year!
2. A condition of existing or functioning in harmony or in congenial combination: Lisa's computer programs do not have compatibility with the kind of programs Mary has on her computer, so Lisa can't use such programs on her own computer because they wouldn't work!