Avocado or Aguacate , Avo or cado.
Avo has been slang for a long time now, an add on to your sandwich, Burrito, salad .... Whatever, It's understood " Add Avo PLease"
" Side of Avo please" . It rolls off your tounge and is a pleasant abbreviation.
Living in ground zero for slang creation , new words for old things are not uncommon. I can't recall a slang word I have less fondness for than 'cado. It sound's ....bad, like it's made up by people who dislike vegetables and fruit in general . My redneck family member's would have a hard time pronouncing Avocado or Avo without feeling silly, but I know they are comfortable with the rough and tumble 'cado, whatever the hell that is. " I got some "cado here , you want some?" . No, I do not. It sounds like fried alligator entrails and no one know's what your talking about in not a good way. Avocado is a most highly revered fruit for many people's , unduplicatable in it's content and unique all the way around. Thus as it was debated over 100 years ago , Avocado or Aguacate, the made up word , Avocado won out and hence we face this great debate of minor importance to those whose diet and livelihood do not depend on it, but this is serious fruit business.