Yeah, I am working on a text search method as well. It will allow people to search for keywords as well as more specific query, such as integral(velocity), derivative(position), (velocity)^2, ect. I just haven't finished coding this portion yet. I agree that it can be somewhat difficult to understand what each variable/keyword means, maybe I could put a general page with a definition of each entry? The problem is most of these things are not really standardize and have equivalent meanings. For example, what does "height" or "length" mean? But, the equation PE = mgh contains the variable commonly known as "height", so you can't just ignore this fact and replace the tag "height" for "displacement" or "relative position" because then people would not be able to find what they are looking for since they are used to the common name. An alternative idea I had to selecting the common names of variables was to search base on the dimension of the variables, such as "height" would become "meters". This would help standardize, but the problem is many users probably don't know what the dimension of the variables they use are like Magnetic flux density (kg *s−2 *A−1) or Capacitance (kg−1 *m−2 *A2 *s4), so that would only benefit advanced users. I wanted to make a tool anyone could use to find the equation they need for a homework problem, ect. If anyone has any ideas about this issue, you can email me through the contact page of my website or post them here.