Tap
A tap, or tapping, is a term used in the Super Smash Bros. series that refers to quickly tilting, or tilting in a direction very hard, on the control stick/d-pad in a certain direction. It is used to either dash, jump, jump in mid-air, jump from a platform, and can be combined with the attack button to perform smash attacks.
Different ways to use tapping
There is a number of ways to use taps, as mentioned above. Note that for the Wii remote, the equivalent to tapping is double tap, as tapping normally would act as a tilt.
Dash
A player can dash by tapping the Control Stick/D-Pad left or right.
Jump
A player can jump by tapping upwards on the Control Stick. Midair jumps, jumps out of water and edge jumps can also be performed this way.
In both Brawl, and Super Smash Bros. for Nintendo 3DS, tapping up to jump can be disabled in the Controls menu for the two games. Within tournaments, most players prefer disabling tap jump, as it can lead to mechanical errors dealing with up specials or up tilts, among other attacks. This does not, however, disable tap jumping out of water or from the ledge.
Platform drop
A player can fall through a soft platform by tapping the Control Stick/D-Pad downwards.
Smash attack
Smash attacks are attacks that can be performed by tapping the Control Stick/D-pad in a direction while simultaneously pressings the grab or attack button.