https://en.wikipedia.org/wiki/Single...t#Nomenclature
The above article gives some notes about the nomenclature of the rounds in an elimination tournament. As you can see, "Octofinals" is used by the North American Debating Championship.
What's really great is that they use "Double-octofinals" or "Decimosextofinals" for the round of 32 and "Triple-" or "Quadruple-Octofinals" after that.
Maybe the FIRST nomenclature person was on a debate team?