This is the typical conversational English term used for a unit of Taiwan currency. Apparantly it stands for the "New Taiwan dollar". You will often see (in English) the notation NT$100, or less frequently TW$100, or 100 TWD. Ex. "That will be 12 NT." "I'm one NT short." Alternatively some people just call them "dollars". The exchange rate has fluctuated and is around 30 NT to one US dollar.