We don't have synonyms for bressummer yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are brestsummer, bressumer and breastsummer.
(n) :
(architecture) A large, horizontal supporting beam which bears the weight of a wall starting on a first or higher floor, particularly when exposed or used to support a jetty (timber-frame overhang construction).
(n) :
(architecture) A large, horizontal supporting beam which bears the weight of a wall starting on a first or higher floor, particularly when exposed or used to support a jetty (timber-frame overhang construction).