Definition
A property of a material whose physical characteristics — such as strength, stiffness, or conductivity — are different when measured in different directions. An anisotropic material does not behave the same way along every axis.
Plain English
The material is stronger or stiffer in one direction than another. How it behaves depends on which way you push, pull, or measure it.
Context Anchor
Seen in aircraft materials, structural repair, wood construction, and composite repair discussions.
Derivation
From Greek 'an-' (not) + 'isos' (equal) + 'tropos' (direction or turn). Literally 'not equal in all directions.' Knowing this makes the meaning easy to hold: the material's properties are not the same whichever way you turn it.
Why Pilots Care
Aircraft structures made from composites or wood rely on correct fiber or grain orientation; misalignment can reduce strength and lead to failure.
Analogy
Wood is a simple example: it is usually easier to split along the grain than across it. The wood has different strength depending on direction, which is the basic idea of anisotropic behavior.
Intuition Check
Anisotropic does not mean simply “uneven” or “irregular.” It means the material’s behavior changes with direction.
Example Sentence 1
Wood is anisotropic, so a wooden spar is much stronger along the grain than across it.
Example Sentence 2
Inspectors checked the grain direction on the wooden spar, knowing that anisotropic wood is weakest when stressed across the grain.