Question

what is meant by buffer in electronics??

Answer 1

I think you mean a buffer amplifier.

A buffer is a unity gain amplifier packaged in an integrated circuit. Its function is to provide sufficient drive capability to pass signals or data bits along to a succeeding stage. Voltage buffers increase available current for low impedance inputs while retaining the voltage level. Current buffers do just the opposite, keeping the current the same while driving high impedance inputs at higher voltage levels. In either case, the buffer protects and the output of the supplying device while providing a sufficiently robust signal to the next stage. Some data buffers are bi-directional, allowing data to pass in either direction. Others are tri-state devices with a disabled state that enablese several device outputs to connect to the same input.
http://yourbusiness.azcentral.com/buffer-electronics-20738.html

Answer 2

http://en.wikipedia.org/wiki/Buffer_amplifier
Wikipedia has info, too.
Wikipedia isn't necessarily reliable, but, if you need, it might point you in a helpful direction.

If you need digital buffer (logic) information, I found this: http://www.electronics-tutorials.ws/logic/logic_9.html
I think that site is generally good for the concepts of basic components.

Answer 3

In a fiber optic cable, a buffer is one type of component used to encapsulate one or more optical fibers for the purpose of providing such functions as mechanical isolation, protection from physical damage and fiber identification.