Note that crosscutting is a relationship between representations of concerns. Note also that it is a symmetric relationship. Therefore, if:
- A is a representation of one concern,
- B is a representation of another concern, and
- A crosscuts B,
then B also crosscuts A.
This means that the term "crosscutting concerns" is often misused in two ways: To talk about a single concern, and to talk about concerns rather than representations of concerns. Consider "synchronization is a crosscutting concern": we don't know that synchronization is crosscutting unless we know what it crosscuts. And there may be representations of the concerns involved that are not crosscutting.
The reason we still say "crosscutting concern" is that when we do so, we are relying on the surrounding Dominant Decomposition to provide a reference with which the crosscutting concern crosscuts.