See the definition inside
According to HUD(US Department of Housing and Urban Devlopment). The definition of A first-time homebuyer is an individual who meets any one of the following criteria:
1)An individual who has had no ownership in a principal residence during the 3-year period ending on the date of purchase of the property. This includes a spouse (if either meets the above test, they are considered first-time homebuyers).
2)A single parent who has only owned with a former spouse while married.
3)An individual who is a displaced homemaker and has only owned with a spouse.
4)An individual who has only owned a principal residence not permanently affixed to a permanent foundation in accordance with applicable regulations.
5)An individual who has only owned a property that was not in compliance with State, local or model building codes and which cannot be brought into compliance for less than the cost of constructing a permanent structure.