Definition from Nolo’s Plain-English Law Dictionary
Title to property acquired by someone after that person has purportedly transferred the property to someone else. As soon as the seller actually acquires title, it passes to the person to whom it was sold. For example, John signs, acknowledges, and records a deed of his late father's ranch to Sam, even though John has not yet received title from his father's estate. When John gets the title from his father's estate and records it, the after-acquired title goes automatically to Sam.