Pylon

[peterparker]

What is this word's origin? Prefix 'py' something to do with heat?

[Quizmonster]

It comes from the Greek for gate and was often used specifically for a gate-tower. Thus, by the 1920s, it had taken on the meaning in English of a high structure supporting cables.

[Peter Pedant]

Yeah the Gk word is pule
pronounced by us oldsters as poo-lee

so the prefix is pyl, and not py

The latin word is porta (and although Dixie my latin master said there was no relation, in fact if you look at it long enough........ and anyway they are both related indo european languages)

the py you were thining about is in fact pyr
(pyrex dish, pyrexia, pyrexial),
and yes that does mean heat, fire