Ask HN: Is the name R2 short enough to be free of trademark?

If so, it would be amazing if those of us who feel like it could name our chatbot projects "My Cool Chatbot RELEASE 2" and say "Hey R2" for the wake phrase, even for commercial use!

I do feel that there should be a strong case to be made that 2 characters should not be a long enough name to qualify as brandable.

I hope so; would love to hear from you all! If this is legal I am ABSOLUTELY going to release various bots called R2. One of the best things about the R2 name is it feels gender neutral, which is beneficial as a default: (see https://en.unesco.org/EQUALS/voice-assistants )