What Does That Mean?

My nephew Ben (3) enjoys playing with those Fisher Price magnetic plastic letters that so many people have on their refrigerators, including my brother and sister-in-law. He knows how to sound out certain sounds already, and can spell certain names such as Ben or Imma.

Of course, he sometimes moves around letters and sounds it out - then asks what it means. A few days ago, he switched the "A" and "M" in Imma.

Ben: Ee-MOM. What's an Imam?

[pause]

SIL: Umm... Nothing.

Some answers are just easier.