"namespace clutter" in mathematics In programming, if you had a lot of functions and variables defined such that loading new functions / variables overwrites existing ones, you'd call it namespace clutter (or at least, that's one term for it).
In mathematics (or science disciplines), is there a similar term?  e.g., the constant h could be used for both the height of an object and Planck's constant in the same document (or formula).  
 A: I don't think there is any standard term for it. 
In general, mathematicians try their best to be precise and unambiguous (this is not to say that they always succeed). It is considered bad practice to "overload" terminology and notation if it can be potential causes for confusion, and in publishing papers those are often considered to be "errors" that referees and/or editors would want the author(s) to fix before accepting a paper for publication. 
A side effect of this being that if a paper spans two fields with overlapping notation, for the sake of clarity the paper will most likely "go against convention" used in one, if not both, of the fields. 
A: Unlike a computer, who can't tell the difference between identically named variables, humans are generally a lot better at using contextual information. 
Therefore, in mathematics and other sciences this is rarely if ever a problem. For instance, it is not rare to see the letter $i$ used both as an index as well as $\sqrt{-1}$ in the same equation.
A: In English this is called Homonyms, same spelling, same pronunciation but different meaning.
A good example is the Mathematical $i$ in electrical engineering becoming $j$ to avoid confusion with the same symbol for current.
They are examples of context sensitive/dependent symbols.
