Tipper
The term tipper can be used as a general term of reference for hitting with the tip of any attack, but is usually used in terms of the Home-Run Contest and Marth and Roy's attacks. It can also be used to refer to Ganondorf's tipped reverse uair.
Tipper (Home-Run Contest)
A tipper occurs when one hits Sandbag with the tip of the bat during a bat smash. It deals 20% damage to Sandbag and sends it farther than other bat swings (a close hit or midhit). This is the usual method of finishing Sandbag, unless the character has an attack that is stronger such as a Warlock Punch.
An aerial tipper is a tipper in which one hits Sandbag while it is still in the air. It sends Sandbag farther than a normal tipper.
Tipper (Marth and Roy)
Outside of Home-Run Contest, "tipper" is typically used in reference to Marth and Roy's attacks. Marth's tippers are stronger than his center hits; Roy's tippers are weaker.
Tipper (Ganondorf)
The up air attack of Ganondorf is a counterclockwise bicycle kick; while the inner leg provides a strong attack capable of KOing at higher percentages, the tip of the foot can override almost any attack and, while producing a small amount of backwards knockback, provides a huge amount of hitstun, easily enough to KO even Marth should he be off-stage on most maps.
The term "tipper" can also be used with Bowser's forward smash and a few other attacks.