Cylinders
The chambers where fuel burns. Common counts are 3, 4, 6, and 8.
Cylinders are the chambers inside an engine where fuel burns to make power. The count is shorthand for engine character: more cylinders generally means more power, more smoothness, and more fuel use.
Four cylinder engines dominate modern lineups because turbocharging lets a small engine make the power a V6 once did. Six and eight cylinder engines remain common in trucks, large SUVs, and performance cars.
From the data: Of the 19,491 trims in the Trimslate dataset, 7,681 have a four cylinder engine.