Definition
A theory of forgetting which holds that a memory, skill, or piece of knowledge fades and weakens over time when it is not practiced, recalled, or applied. The longer something goes unused, the harder it becomes to retrieve or perform.
Plain English
If you don't use what you've learned, you slowly lose it. Skills and knowledge fade when they sit untouched.
Context Anchor
Seen in aviation instructor discussions of memory, forgetting, skill retention, and the need for regular practice.
Derivation
From the prefix 'dis-' meaning 'not' or 'opposite of,' combined with 'use.' Literally 'not using.' The aviation-instruction meaning extends this to the natural fading of learning that happens when knowledge or skills are not exercised.
Why Pilots Care
Unaddressed disuse can degrade critical piloting skills and increase risk during flight.
Analogy
A rarely used trail can become overgrown. In the same way, a rarely used skill can become harder to follow smoothly.
Intuition Check
Disuse does not mean the knowledge was never learned. It means it was learned, but weakened because it was not used.
Example Sentence 1
The instructor scheduled regular review sessions to counter the effects of disuse on the student's emergency procedures.
Example Sentence 2
Regular simulator sessions help prevent disuse from eroding instrument scan proficiency.