Totum pro parte is a Latin phrase that means "the whole for a part". It is used to describe a situation where something is represented by a smaller part of it.
For example, if you have a toy car with four wheels and you lose one of the wheels, you can still say, "I have a car with four wheels," even though it only has three. In this case, the whole car is represented by one part - the number of wheels it has.
Another example could be a basketball team. Even if one player is subbed out, the team can still be referred to as a whole team even with one lesser player.
Overall, totum pro parte is just a fancy way of saying that you can still talk about the whole of something even if it's missing a part.