Glossary
What is the downwind leg?
The leg of the traffic pattern flown parallel to the runway and off to one side of it, travelling in the opposite direction to the landing. Most pattern radio calls and the pre-landing checks happen along it.
Also called Downwind
That is the whole entry for now. The longer version, with the mechanics and worked examples, is still to be written. See autorotation for how those read once they exist.