We don't have synonyms for trone yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are tone, prone and trove.
(n) :
(UK, dialect, Scotland, obsolete or historical) A type of steelyard (weighing machine) for heavy wares, such as wool, consisting of two horizontal bars crossing each other, beaked at the extremities, and supported by a wooden pillar.
(n) :
(UK, dialect, Scotland, obsolete or historical) A type of steelyard (weighing machine) for heavy wares, such as wool, consisting of two horizontal bars crossing each other, beaked at the extremities, and supported by a wooden pillar.