This is a puzzle I have used with my school students, and I am wondering if it already has a name. The idea is to give a string of (often three) letters and to find a word with that string of letters in the middle. Usually I just write the string with a * before and after, saying you have to replace the *'s with any nonempty strings of letters, even not the same strings, to make a real word.
* rfl *
* atm *
* pbo *
Is there a name for this kind of puzzle?