Imagine you have a box filled with toy cars. You can take out a car and move it around in any direction you want. Now, imagine this box is actually a space where mathematical functions live. These functions can also move around in many different directions.
A locally convex topological vector space is a special kind of mathematical space where functions can move around in many different directions, just like in the toy car box. However, this space also has a specific shape that follows some rules.
The "topological" part of the name means that the space behaves in a very particular way when we look at it closely. We might see that if two functions are very close together in this space, they are also very similar in some way. We can also use this space to talk about limits and continuity, just like we do with numbers.
The "locally convex" part of the name means that we can find a bunch of little sub-spaces inside this big space that act just like this big space. It's like breaking up the toy car box into smaller sections that behave the same way as the original box.
So, a locally convex topological vector space is a space where functions can move around in any direction, but we also have specific rules that allow us to understand how these functions behave and how we can break the space up into smaller, similar pieces.