What do the following words have in common that has nothing to do with their meanings?

1. CORAL

2. TAXING

3. HOLY

4. MOUSE

5. LITER

6. CARTON

Answer:

 

Each word could have one of its letters doubled to make a new word:

 

1. CORAL - CORRAL

2. TAXING - TAXIING

3. HOLY - HOLLY

4. MOUSE - MOUSSE

5. LITER - LITTER

6. CARTON - CARTOON