Definition
A system or procedure that prevents ice from forming on aircraft surfaces or components by activating before ice accumulation begins. Anti-icing is preventive — it is turned on in advance of, or upon entering, icing conditions to keep protected surfaces clean.
Plain English
Anti-icing means stopping ice from forming in the first place. You turn the system on before ice can build up, so the protected parts stay clear.
Context Anchor
Seen in aircraft systems discussions, winter operations, preflight planning, and checklist items for operating in visible moisture near freezing temperatures.
Derivation
From the prefix 'anti-' (Latin/Greek, meaning 'against' or 'preventing') combined with 'icing.' The word literally means 'against ice forming' — which captures the key idea: it acts before ice appears, not after.
Why Pilots Care
Ice on wings or control surfaces reduces lift, increases drag, and can make the aircraft uncontrollable; anti-icing systems allow continued safe flight when conditions would otherwise force a diversion or landing.
Intuition Check
Anti-icing does not mean removing a heavy layer of ice after it is already there. It means preventing ice from forming or keeping early ice from building up.
Example Sentence 1
Before entering the cloud layer where icing was forecast, the pilot turned on the anti-icing system to keep the leading edges clear.
Example Sentence 2
Anti-icing fluid was applied to the propeller blades during preflight to protect them while flying through freezing drizzle.