Learner's definition of DIMENSION
1 : the length, width, height, or depth of something : a measurement in one direction (such as the distance from the ceiling to the floor in a room)
She carefully measured each dimension of the room.
The room's dimensions [=its length, width, and height] were surprisingly small.
2 : the amount or number of things that something affects or influences — usually plural
We underestimated the dimensions [=extent, range] of this problem.
the vast dimensions [=magnitude, scope] of the disaster
3 : a part of something
There are many dimensions [=aspects] to the problem.
The social/political/religious dimensions of the problem must also be taken into account.
The more powerful engine gives this car a (whole) new dimension. [=makes the car very different]
— usually used in combination