HMS Peony was a of the Royal Navy.
Wolfgang Amadeus Mozart began his series of preserved piano concertos with four that he wrote at the age of 11, in Salzburg: K. 37 and 39–41.
Potassium-40 (40K) is a radioactive isotope of potassium which has a very long half-life of 1.251 years.
Toyota Motor Corporation's K family is a series of 4 and 5-speed light/medium-duty transmissions found in Toyota Corollas and Starlets.
The Veer-class corvettes of the Indian Navy are a customized Indian variant of the Soviet.