Question

An expense that has been incurred but not yet paid is called​ a(n) ________.

Answer 1

An expense that has been incurred but not yet paid is called​ an accrued expense.
An expense is categorized into many types according their property, like discount expense, depreciation expense, prepaid expense etc 
Salaries payable and interest payable are the examples of Accrued expense, salaries payable are for one accounting period, they are not paid until the next.