Hi Bharath
to try and explain at least some of it:
Track: is the copper foil left after the etching process and is literally the piece of copper wire that joins components together.
Pad: components are placed such that each of their leads is soldered to a pad which is a suitable shape and size to receive them.
Pore? Do you mean Pour?: Imagine you have a large region which you wish to fill with copper. One of the ways to do this is to mark or draw the outline of the region and use the POUR command to let the program fill that region rather than use individual 'lines' of copper.
Via: A means of connecting tracks on each side of the board such that one track is joined to another VIA a through board connection. This usually done with a small pad on each side and a continuous copper connection through the board. Another type of VIA is used sometimes on multilayer boards, it's called a buried via and this means that one or both of the via pads is not visible on a surface board layer.
Assy: This is usually a contraction of the word 'Assembly'
Silkscreen: When populating or stuffing components onto a PCB, life is generally much easier if an image of each component and/or its reference number is printed on the PCB a process known as silk screening.
Finally, Route can be used as a verb meaning join two pads together. It can also allude the to the twists and turns necessary to join a track between two pads.
Hope this helps
Ed