Most often appears in compounds: 通货膨胀 (tōnghuòpéngzhàng, inflation) and 通货紧缩 (tōnghuòjǐnsuō, deflation). On its own 通货 sounds technical - everyday speech uses 货币 (huòbì) for 'currency.'
memory
通 (to circulate) + 货 (goods/money) - literally 'circulating money,' the textbook definition of currency.
