অর্থ : An event in which one thing is substituted for another.
							উদাহরণ : 
							The replacement of lost blood by a transfusion of donor blood.
							
সমার্থক : replacement, substitution, switch, transposition
অর্থ : The act of changing the arrangement of a given number of elements.
অর্থ : Complete change in character or condition.
							উদাহরণ : 
							The permutations...taking place in the physical world.
							
অর্থ : Act of changing the lineal order of objects in a group.