Souse can mean to cover a food in liquid, to plunge a food in liquid, or it can refer to the liquid that is used.
Sousing something can be for the purposes of cooking or pickling.
For cooking, the liquid is often a spiced vinegar solution. For pickling, the liquid is usually brine or a vinegar.
In the Bahamas, a souse is a meat broth with onions, lime juice, celery, and peppers. The meat can typically be oxtail, pig’s feet, sheep’s tongue, or chicken.
In English slang, to be “soused” is to be pickled, as in drunk.