Unit of engine capacity

LITER

Think of the metric measurement often seen on a car’s badge indicating its power output.

The clue "Unit of engine capacity" refers to how an engine's size is measured, often seen in car specs like "2.0L." The answer is "LITER," short for liters, which quantifies the total volume of an engine's cylinders. It’s a straightforward definition with no wordplay—just a common term in automotive contexts.