  Theta-vexillary signed permutations are elements in the hyperoctahedral group
that index certain classes of degeneracy loci of type B and C. These
permutations are described using triples of $s$-tuples of integers subject to
specific conditions. The objective of this work is to present different
characterizations of theta-vexillary signed permutations, describing them in
terms of corners in the Rothe diagram and pattern avoidance.
