Odds-on favorite

What’s the difference between a favorite and an odds-on favorite? I started wondering about this after reading about the death of Seattle Slew.

Odds-on pays less than even money.

Think 1-5 instead of 5-1.

In Oz, odds of 5-1 mean bookies think the horse has a 1 in 6 chance of winning. 5-1 on means 5 in 6 chance of winning.