The term “tom-next” refers to “tomorrow next day”. Sometimes, it is called the cost of carry. In the same way as trading futures, a Forex trade could end up with the trader having to accept the delivery of their traded asset should they fail to close out on their contract before it expires. When you trade in Forex, note that the date of delivery is 2 days following the transaction, however the majority of Forex traders are purely speculators who never intend to take delivery of the currency they have chosen.