We don't have synonyms for tannat yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are bannat, annat and tanna.
(N) :
a red wine grape, historically grown in South West France in the Madiran AOC, and is now one of the most prominent grapes in Uruguay, where it is considered the "national grape".
(N) :
a red wine grape, historically grown in South West France in the Madiran AOC, and is now one of the most prominent grapes in Uruguay, where it is considered the "national grape".