"Overvote" means a ballot on which a voter casts a vote for a greater number of candidates or positions than the number for which he was lawfully entitled to vote and no vote shall be counted with respect to that office or issue.
"Undervote" means a ballot on which a voter casts a vote for a lesser number of candidates or positions than the number for which he was lawfully entitled to vote.
Va. Code § 24.2-802.2