Etymology of "broma"

Question

According to dictionaries, this word comes from the Ancient Greek word βρῶμα (brôma), which has the following meanings:

1. a shipworm (Teredo navalis) that bores into wooden piers, ships, etc.
2. that which is eaten, food, meat
3. (dentistry) cavity

None of these translations have anything funny about them. How, then, did broma come to mean joke in Spanish?

Answer 1

You got the right source with definition #1. That shipworm eats into things (the ship hull). A broma is played on someone and eats that person a little bit (lets say that the annoyance of the joke eats him, or gets into him, like that worm that eats the wood).

The origin of the word is closer to mockery and deceit, thus implying that a broma would annoy someone.

Also, the word abrumar has apparently the same etymology.

Abrumar

1- Agobiar con un peso grave.

2- Producir tedio o hastío.

3- Producir asombro o admiración.

So with abrumar you can be overloaded by both positive and negative emotions. This reference explains the etymology, but basically, the same way that a ship would be dragged or by the perforations in the hull done by these shipworms (an encumbrance or impediment to sail), a person would be by emotions (something in you that becomes a burden).