hi @srbk95 !!
Welcome to our community 
Sorry for the delay here.
That’s an interesting question.
The text2vec-contextionary is really not being used according to some stats we have, so I don’t think that’s an interesting path to follow.
fine tuning your model may be a long and expensive path.
One alternative way I can think of is to create your own collection of abbreviations. Before performing the hybrid search, you will search that abbreviation collection and add the most relevant abbreviations to the prompt. 
Another alternative is to add those abbreviations before ingesting the content…
Any way, let me know if you were able to come with some alternatives.
Thanks!