venous sinus
General anatomical term for a large vein or channel carrying venous blood, such as the dural venous sinuses.
The dural venous sinuses collect venous blood from the brain.
sinus venosus
Specifically refers to the sinus venosus, a developmental structure in the embryonic heart that later forms part of the right atrium.
In the fetal heart, the sinus venosus becomes part of the right atrium.