Every designer needs to understand typography.
Typography is, quite simply, the art and technique of arranging type. It’s central to the work and skills of a designer and is about much more than making the words legible.
Your choice of typeface and how you make it work with your layout, grid, colour scheme, design theme and so on will make the difference between a good, bad and great design.
Good typography is partly down to creative intuition, but it’s impossible to become skilled in typography without understanding the basic rules of the craft – even if you mean to break them.
In the following article, fundamental concepts of typography are introduced, followed by a detailed glossary of its main terms: http://www.creativebloq.com/typography/what-is-typography-123652