What spelling rule applies to the word stopped?

The spelling rule that applies to the word "stopped" is the "dropping the final -e" rule.

Here's how it works:

1. Base word: The base word is "stop".

2. Adding a suffix: We add the suffix "-ed" to form the past tense.

3. Final -e: The base word "stop" ends in a silent "-e".

4. Dropping the -e: When adding a suffix that begins with a vowel (like "-ed"), we drop the final "-e" of the base word.

Therefore, "stop" + "-ed" becomes "stopped".