the.com/muscle fiber

means A muscle fiber is one long, thin cell — a basic building block of skeletal muscle — specialized to contract and generate force.

from Straightforward compound: 'muscle' traces back through French to Latin musculus, literally 'little mouse,' because an anatomist once thought a flexing bicep looked like a mouse rippling under the skin; 'fiber' comes from Latin fibra, meaning a thread or filament of tissue. Put them together and you get exactly what it describes — a thread-like unit of the 'little mouse' muscle.