Question

what is meant by resistance ?

Answer 1

Resistance is the opposition that a substance offers to the flow of electric current.  It is represented by the uppercase letter R.  The standard unit of resistance is the ohm, sometimes written out as a word, and sometimes symbolized by the uppercase Greek letter omega: 

Answer 2

Hey mate, here is your answer.: -)

Resistance is the opposition that a substance offers to the flow of electric current. ... When an electric current of one ampere passes through a component across which a potential difference (voltage) of one volt exists, then the resistance of that component is one ohm.

HOPE it helps to you!!!