The sales manager meets with the accounting manager in order to clarify aspects of the sales compensation program. This meeting is an example of communication.

The answer is Lateral communication.

Explanation:

Lateral communication describes the exchange of ideas or information between people who belong to a peer group, community, department or unit of an organization.

Such people must be of the same rank or hierarchical level and the purpose of the communication between them should be aimed at coordinating activities in order to achieve a common goal.

As you might have observed in the question, the sales manager and accounting manager are both mangers (the same hierarchical level) and belong to the same department of the organization.