Symbol of an op-amp is triangle only.why?

[iwasgod]

help me here...symbol of an op-amp is triangular in shape...i need reason for this...why it is so...or where i can find regarding this..
similar que for transistor also...

 

[mgb_phys]

The symbol is totally arbitrary, somebody thought it up and other people copied it.
Rememebr how you draw it in a schematic has no relation to how the real part actually looks.

A triangle makes sense because there are 3 important connections to an opamp (2inputs and 1output) and there is a sense of direction, the inputs go toward the output so a shape like an arrow fits.