The Dictionary of Mathematics provides free definitions for over 6,000 of even the most technical mathematical terms.

This dictionary covers all commonly encountered terms and concepts from pure and applied mathematics and statistics, such as linear algebra, optimization, nonlinear equations, and differential equations. In addition, there are entries on major mathematicians and topics of more general interest, such as fractals, game theory, and chaos.
Cover almost all maths formulas and we are adding more and more formulas