accommodate
Two Cs, two Ms. It accommodates both.
-
Wrong: accomodate
Right: accommodate
Two Cs and two Ms.
The trick
It’s a big word, so it accommodates two of everything—two Cs and two Ms.
Regularly tops the list of most-looked-up misspellings. The usual failure is one M, because accomodate looks reasonable and sounds identical.
Now go double both letters.