Learner's definition of DIFFERENCE
1 : the quality that makes one person or thing unlike another
◊ To tell the difference between two people or things is to see how they are unlike each other.
It's hard to tell the difference [=distinguish] between one action movie and another.
The new version is supposed to be much better than the old one, but I can't tell the difference (between them).
2 [count] : something that people do not agree about : a disagreement in opinion
They've always had their differences. [=they have always disagreed about some things]
The debate gave them a chance to air their differences. [=to discuss the things that they disagree about]
We need to find a way to resolve/settle our differences. [=to stop disagreeing, arguing, etc.]
There seems to be a difference of opinion [=people disagree] about what we should do next.
They divorced because of irreconcilable differences. [=serious disagreements that they were not able to settle]
3 [count] : the degree or amount by which things differ
make a difference
1 : to cause a change : to be important in some way
Cost can make a difference in deciding on a college.
“When would you like to leave?” “It makes no difference (to me).” [=it doesn't matter to me; I don't care]
The weather didn't make any difference in our plans. [=didn't change our plans]
It would make a lot of difference if you came.
Your help made a big difference.
It makes very little difference. [=it matters very little]
The size of the engine can make all the difference. [=can be very important; can matter most]
It may not matter to you, but it makes all the difference in the world to me. = It makes a world of difference to me. [=it matters very much to me]
2 : to do something that is important : to do something that helps people or makes the world a better place
same differencechiefly US, informal
— used to say that two things are not really different in any important way
what's the difference?
1 — used to ask how one thing is different from another 2
orwhat difference does it/that make? — used to ask why something is important or to suggest that something is not important