efficiency

C1 · Advanced Countable noun Science Technical

n. the ratio of useful work or energy produced compared to the energy put in.

n. the ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in.

“Most car engines have a thermal efficiency of only about twenty-five percent.”

“Engineers are constantly seeking to increase the aerodynamic efficiency of the aircraft to reduce fuel consumption during long-haul flights.”

C1 · Advanced Countable noun American English

n. a small apartment that usually has only one main room for living and sleeping.

n. a small, self-contained apartment, typically consisting of a single main room with a small kitchen area and a bathroom.

“He rented a small efficiency near the university to save money on rent.”

“The building offers several efficiencies that are ideal for single professionals who prioritize a central location over square footage.”

C2 · Proficiency Uncountable noun Archaic · Formal

n. the power or ability to produce a specific result.

n. the capacity or power to produce a desired effect or result.

“The old books spoke of the efficiency of certain herbs in curing fevers.”

“The philosopher questioned the efficiency of the law in truly changing human behaviour rather than merely punishing it.”