Definition
Anything that has mass and occupies space. Matter exists in three primary physical states — solid, liquid, and gas — and can change between these states when energy is added or removed.
Plain English
Any physical 'stuff' that takes up room and has weight. Air, fuel, oil, metal, water — all of it is matter.
Context Anchor
Seen in basic science and maintenance discussions when explaining materials, fluids, gases, pressure, and how aircraft parts behave.
Derivation
From the Latin materia, meaning 'substance' or 'stuff things are made of.' The aviation usage keeps that simple meaning — the physical material that makes up an object or fluid.
Why Pilots Care
Understanding matter and its states underpins how engines burn fuel, how hydraulic systems transmit force through liquid, how pneumatic systems use compressed gas, and how temperature and pressure changes affect aircraft components.
Grounding Statement
If you can weigh it or it takes up space — even invisibly, like the air in a tire — it's matter.
Intuition Check
Do not read matter here as “a problem” or “a subject,” as in “what’s the matter?” In this context, matter means physical substance.
Example Sentence 1
The technician explained that all three states of matter — solid, liquid, and gas — are present in a running engine: metal parts, oil, and combustion gases.
Example Sentence 2
Different states of matter respond differently when exposed to the pressures and temperatures found in flight.