The chat shorthand that started me thinking on this was
oic which represents
Oh, I see.
This is not an Acronym or an Initialism, as both of those are based on spelling.
This is not just a shortened form of a word, like “ex.” for “example”. Though that is just an Abbreviation, neither an acronym nor an initialism, it is still based on spelling.
This is not an Onomatopoeia, a word crafted to be similar to the sound it represents, as pronouncing this would be so close to the sound a pig makes.
This is shorthand needing another way of interpretation to be properly understood. Abbreviation is the closest term that I know for something like this, but it does not seem to fit. Does anyone know a term for this kind of word? Just curious. Perhaps giving it a term would legitimize it too much.