Accountable Plan

What Does Accountable Plan Mean?
A plan for reimbursing employees for business expenses. Under this plan, the reimbursement that the employee receives for the expenses is not included in his/her income. Employees are required to account adequately for expenses with records and return any excess reimbursement within a reasonable period of time.

Investopedia explains Accountable Plan
Expenses can include such things as travel, meals, lodging, entertainment, transportation, or any other costs incurred for business purposes. In the past, companies' business expenses were less thoroughly scrutinized. This was partially due to unjustified expenses that were being used as tax write-offs.