The solution in which there is a negligible change of ph value, even after the addition of 1/2 drops of acid or base.
Mixture of a weak acid and weak base or it could be vice versa
a solution which resists changes in pH when acid or alkali is added to it.Is a buffer solution.Not that one
Buffer solution is solution consisting mixture of weak acid and conjugate base.

namaskar bhai log… pahchane… kaise ho dono….
Good evening bhai….haa thik hi hai….hope you too…?
Buffer solutionThey are those solutions which has a constant value of pH , no matter what we add in to them .Example: The pH of Blood is 7.4-7.6. Blood act as a buffer. As u all know, in spite of eating so many types of food items, the pH of blood remains same.The buffer solution is defined as:\xa0A solution which resists the change in hydrogen ion concentration on addition of a small amount of acid or a base in to it.
A solution that only changes slightly when an acid or a base is added to it. For an acid -buffer solution, it consists of a week acid and it\’s conjugate base . For a base buffer solution,it consists of a week base and it\’s conjugate acid. ??

The solutions which resist change in pH on dilution or with the addition of small amounts of acid or alkali are called Buffer solutions.

A solution which can resist any change in PH when a small amount of acid or base is added is called buffer solution