ad valorem Meaning, Definition & Usage

  1. adverb in proportion to the estimated value of the goods taxed
    ad val.
    • the goods were taxed ad valorem

WordNet

Ad va*lo"rem
Etymology
L., according to the value.
Definitions
  1. (Com.) A term used to denote a duty or charge laid upon goods, at a certain rate per cent upon their value, as stated in their invoice, -- in opposition to a specific sum upon a given quantity or number; as, an ad valorem duty of twenty per cent.

Webster 1913