Vex, as in vertex. Bulging outwards. I think the proper way to remember those (I've struggled with them too) is actually use them a lot. For example, some mathe

Vex, as in vertex. Bulging outwards. I think the proper way to remember those (I've struggled with them too) is actually use them a lot. For example, some mathematicians study convex geometry, which is a meaningful subject on its own. *(lazy ninja edit)