Once we got onto the subject of words, I started thinking about how words can be distinguished not by their meaning, but by their lexical form.
For example, suppose we consider every word in the English language that, when its letter order is reversed, forms a different word. This evening I did a quick computer analysis, starting from a rather comprehensive word list.
To my surprise, I found only 155 such pairs of words altogether (see below).
Somehow I’d thought there would have been more.