Ability point
The name(s) presented could be conjectural.
The ability point (AP) is the ability power measurement used internally by all games in the Splatoon series.
Primary abilities are worth ten points, and secondary abilities are worth three points. With there being a maximum of three primary abilities and nine secondary abilities, the maximum number of ability points a player can normally have is 57. Some abilities allow players to have higher ability points in theory, but in practice there is no additional effect because the games internally cap ability effects at 57 points.
Some abilities such as 
Opening Gambit can contribute points to multiple pools of ability points.
History
The ability point has behaved consistently between each game in the Splatoon series.
To date, no Splatoon game has informed players of the worth of the large and small ability slots, with manuals and character dialogue only containing basic information. This leaves players to find out for themselves how much each slot type increases their ability point stat.
Examples
Total abilities versus total ability points
Player A equips three secondary slots of 
Swim Speed Up. Player B equips one primary slot of Swim Speed Up. This results in Player A having nine points and Player B having 10 points. Even though Player A has more Swim Speed Up abilities, the underlying point total means that Player B will swim slightly faster.
Ability Doubler
The Splatfest Tee in Splatoon 2 has 
Ability Doubler, which doubles the number of ability points provided by the three secondary slots on the Splatfest Tee. Each secondary ability is worth three points, so there are nine points that Ability Doubler doubles to 18 points. This is one point less than the 19 points normally provided by three secondary slots plus one primary slot. Effectively, players wearing Splatfest Tee have a lower possible maximum of 56 points total.
