We first referred to the two positions of the Rieske
iron-sulfur protein as "proximal" and "distal".
This confused a lot of people, so Tony suggested
calling them "b" and "c" positions.

People asked "proximal or distal to what?".  I learned 
proximal and distal in anatomy, where proximal means 
toward the center or point of attachment, and distal is
the opposite. In the arm, the femur is the bone 
proximal to the elbow, and the ulna is distal to the elbow.
An outstretched arm holds the fingers in a distal position, 
a withdrawn arm holds them in a proximal position.

Now I check the dictionary and proximal can also mean "close".
However there is no corresponding definition for distal
(you cannot say "I was distal from the office when the 
message arrived")(The train staion can be proximal to the 
subway terminal, but it cannot be distal from it) 
so the pair would be proximal and distant.

I get confused when the two positions of inhibitors 
at the Qo site are referred to as proximal and distal.