The word homestead can mean several things.
It could mean a "homestead" claim that was filed under the Homestead Act of 1862 (and which was amended). These claims usually were 160 acres and the in Great Plains and points west, but the amounts can vary depending upon the location and time period. Claimants would be deeded the entire homestead if they lived on the farm for a given number of years and improved it.
A "homestead" also could be referring to that portion of a family's farm containing their actual home and surrounding buildings that often was allowed to the widow if her husband died. This homestead was usually protected from creditors in the event of her husband's death. Sometimes the residence and her actual "dower" would be lumped together as her right of "homestead and dower." The technical definition can vary from state to state--refer to applicable state statutes for a precise definition.