Ombreira (f)
(with) definite article: aFrom "ombro" [shoulder]; Butt piece (lodging the reed) of the drone, for insertion into the stock; NB: Interestingly, in standard Portuguese dictionaries the term is defined as "jamb" (doorway).
Veiga de Oliveira, Ernesto: Instrumentos musicais populares portugueses [1966]. Lisboa, 1982 (2), p.323.