anchor: VALUATION ACCOUNT (ALLOWANCE OR RESERVE) -An account that partly or wholly offsets one or more other accounts; for example, accumulated depreciation is a valuation account related to specific depreciable assets and allowance for bad debts is a valuation account related to accounts receivable.
positive: An account that is used for other accounts to offset the second account.
negative: The one account was forbidden to be used to help the other.