Definition
A flap design feature in which a narrow gap, or slot, is formed between the leading edge of the deflected flap and the trailing edge of the wing. When the flap is extended, high-pressure air from beneath the wing flows through this slot and over the upper surface of the flap, energizing the airflow and delaying separation. This allows the flap to produce more lift at higher deflection angles than a plain or split flap.
Plain English
Slotted means the flap has a small gap built into it. When the flap drops down, air sneaks through that gap and flows over the top of the flap, which keeps the air attached and helps the wing make more lift.
Context Anchor
Seen in discussions of flap types and flap effectiveness, especially when comparing plain, split, slotted, and Fowler flaps.
Derivation
From 'slot' — a narrow opening or groove. The name comes directly from the small gap built into the flap design. Knowing the word literally describes a built-in gap helps the reader picture how the flap works rather than treating 'slotted' as a brand name or arbitrary label.
Why Pilots Care
Slotted flaps let the airplane fly slower without stalling, shortening takeoff and landing distances while increasing safety margins near the ground.
Intuition Check
Do not read slotted as merely “has a groove.” In flap discussions, slotted means the gap has an aerodynamic job: it lets air flow through to help the flap keep working.
Example Sentence 1
Most modern training aircraft use slotted flaps because they produce more lift than plain flaps at the same deflection angle.
Example Sentence 2
Because the aircraft was equipped with slotted flaps, it could operate safely from the short grass runway.