Definition of "allo"
allo1
interjection
Alternative spelling of 'allo (“hello”).
allo2
adjective
comparative more allo, superlative most allo
(informal) Allosexual and/or alloromantic; experiencing sexual and/or romantic attraction.
Quotations
However, being aro adds another layer of urgency. As we get older, a lot of our monogamous allo friends will find their life partner, get married, and have kids.
2021, Izzy, "Live While We're Young: Aromantic Frienships, Youth and Futures", CAMP Magazine (University of Melbourne), Volume 4 (2021), page 20
I would say that it'd help so much if the ace characters would be explicitly acknowledged by the creators, but this doesn't always fix things. In the case of Jughead Jones, his asexuality and aromanticism were explicitly stated, but that didn't stop people from completely disregarding it, to the point where most fanart and fanfiction of him makes him allo.
2021, anonymous, quoted in "Questions Of The Month", AVENues Newsletters, July-September 2021, pages 14-15
noun
plural allos
(informal) One who is allosexual and/or alloromantic.
Quotations
Allos might feel infatuated with a new acquaintance or be more attached to their best friend than to any romantic partner, yet they can deny the possibility of romantic feeling because of the lack of sexual attraction. Allos can wave their hand and say, "There are people I want to sleep with, and I don't want to sleep with you, so it's only platonic."
2020, Angela Chen, Ace: What Asexuality Reveals About Desire, Society, and the Meaning of Sex, page 108