We don't have synonyms for parallel bar yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are parallel bars and parallel bus.
(n) :
A set of apparatus consisting of two horizontal bars at a small distance apart, upon which acts of swinging and holding and jumping and dips are performed.
(n) :
A set of apparatus consisting of two horizontal bars at a small distance apart, upon which acts of swinging and holding and jumping and dips are performed.