badydi'u lujvo

b1=d1 is a defensive building (castle, fortress etc.) for protection of b2 from b3 (enemies, danger).

Cf. nolzda, damba, badbi'u.

In notes:

balku'a
k1 is a Hall in structure k2 surrounded by partitions/walls/ceiling/floor k3 (mass/jo'u).
nolzda
z1 is a palace of/for noble person(s) n1=z2.