Dovbear on the origins of the word 'get' (religious divorce):

Get was first a Sumerian word for document (then written on clay.) It made its way into Rabbinic Hebrew via Aramaic and Akkadian...

Even after it entered Hebrew, the word get meant document. It became our word for one specific type of document, i.e. the divorce document, via specialization, a not-very-unusual type of semantic change. In our own language deer (originally any animal) and girl (any child) also changed via specialization.

Just in case you wondered...