Fragmentation describes a separating of something into pieces. The way a family can be affected by divorce, its members living in separate houses, is one kind of fragmentation.
People often have an image of an exploding bomb when they think about fragmentation, and that sense of something breaking into tiny particles is a useful way to think of the word, no matter how it's used. A burst water balloon experiences fragmentation, and so does a city disrupted by violence. The Latin root word, fragmentum, literally means "a piece broken off," or a fragment.