Where could I learn basic math terminology? I am an english learner and I would like to learn the etymology of Mathematics. I would like to know the most common phrases in Algebra, and Geometry as well. I want to know at a level of 
UK's A+. (If I am right there is something like that in secondary schools)
 A: You might also want to peruse MathWords and Math World.
There is also a handy Math Notation on Math World.
I would also recommend visiting your closest college library and looking through books and math dictionaries.
A: A great place to learn terminology is the Encyclopedia of Mathematics https://www.encyclopediaofmath.org. Additionally, wikipedia is also useful.
A: Well, here is what I would do if I where in your situation. I would go to wikipedia in my language and look for the stuff I want to learn in the other language. Once I got to the page in my language I would click the button on the left that takes you to the english part. ( I recommend this if you allready know what you want to translate)
Something else you can do is pick up a book in english on precalculus. A book that contains a lot of materials and is easy to read (but not very proofy) is Stewart's precalculus. If you read that one you will know most of the definitions.
If you want a free source that gives definitions and provides intuition (but again isn't very proofy) I recommend you take a look at Khan Academy. This can also help you in english in general because Salman Khan speaks in english.
https://www.youtube.com/user/khanacademy/videos?view=1&flow=grid
