How are a common denominator and a common multiple alike and different?

A common denominator is when 2 fractions have the same denominator and a common multiple is when two multiples have at least 1 number alike

Example: Common Denominator

4/10 6/10

Example: Common Multiple

2: 2,4,6,8,10,12
4: 4,8,12

I’m not sure how this works