Mold or Mould?
Your choice!
Mold
Exemple : ‘’I can't find the cake mold!’’
The word "mold" is spelt differently in different variants of English. American English uses the spelling "mold."
Mould
Exemple : ‘’There is mould growing round the windowsill.’’
The British and Australian English spelling also includes a "u" as the word derives from the Latin "modulus" and thus the "u" has been preserved.