I don't know an energy source, but there is the unit of energy, the Joule
j
gravitational potential energy
joule (a unit of energy)
Diesel fuel is a source of energy. It begins with the letter d.
Joule is a science term. It is a unit of energy.
Jump is shouted. It begins with the letter j.
Jade is a color. It begins with J.
Johnstown is a city in Pennsylvania. It begins with the letter J.
The candy that begins with J is Jelly Beans.
A store that begins with the letter J in Michigan is the J Crew store.
Joule is a science term that begins with the letter j. A joule is a unit of energy required to perform a task.
Sheriffs wear a jacket. It begins with the letter j.