The more I search, the more I think I as well as most of us are technically wrong.

Every definition of axle I've just looked at includes the use of "wheels", which pedals are not.

https://en.oxforddictionaries.com/definition/axle
https://www.merriam-webster.com/dictionary/axle
https://en.wikipedia.org/wiki/Axle
https://www.britannica.com/technology/axle