Look up bressummer in Wiktionary, the free dictionary.
A bressummer, breastsummer, summer beam (somier, sommier, sommer, somer, cross-somer, summer, summier,[1] summer-tree,[2] or dorman, dormant tree) is a load-bearing beam in a timber-framed building. The word summer derived from sumpter or French sommier, "a pack horse", meaning "bearing great burden or weight". "To support a superincumbent wall", "any beast of burden", and in this way is similar to a wall plate.
The use and definition of these terms vary but generally a bressummer is a jettysill and a summer is an interior beam supporting ceiling joists, see below:
(UK) In the outward part of the building, and the middle floors (not in the garrets or ground floors) into which the girders are framed. In the inner parts of a building, such beams are called "summers". It is part of the timber-frame construction in the overhanging upper story in jettying.[3]
(UK) "Horizontal beam over a fireplace opening (alternatively lintel, mantel beam), or set forward from the lower part of a building to support a jettied wall, a jetty bressummer".[4]
(UK) "...usually the sill of the upper wall above a jetty; otherwise any beam spanning an opening and supporting a wall above."[5] also called a "jetty sill".
(UK) Breastsummer is a beam in a wall which carries the load over a large opening derived from breast being in the front, mid-level and summer: "A horizontal, bearing beam in a building; spec. the main beam supporting the girders or joists of a floor...".[6]
"a main piece of timber that supports a building, an architrave between two pillars"[7]
"Breast-Summer, an architectural term for a beam employed like a lintel to support the front of a building, is a corruption of bressumer..."[8]
(US) "Summer beam: A large timber spanning a room and supporting smaller floor joists on both sides."[9]
(US) "Summer beam. Heavy main horizontal beam, anchored in gable foundation walls, that supports forebay beams and barn frame above."[10]
^Palmer, Abram Smythe. Folk-Etymology: A Dictionary of Verbal Corruptions or Words Perverted in Form or Meaning, by False Derivation or Mistaken Analogy (1882), quoting Parker's Glossary of Architecture.
^Ensminger, Robert F. The Pennsylvania barn: its origin, evolution, and distribution in North America. Baltimore: Johns Hopkins University Press, 1992. p.392.