In NCERT Class 12 Maths Chapter 1, relations and functions are different concepts:

• Relation: A relation connects elements of one set to another. It is simply a pairing of elements, but it may not follow specific rules. Example: If Set A={1,2,3} and Set B={4,5}, a relation can be {(1,4), (2,5)}.
• Function: A function is a special type of relation where each input has exactly one output. Example: f(x)=x+2 maps every x to a unique value.

Thus, every function is a relation, but not every relation is a function.