leading light 
noun
A person who is prominent or influential in a particular field or organization: Lesley is a leading light in a local netball team...
- He is probably the leading light in the field of Australian improvised music.
- Everyone would have to admit that Graham proved himself a leading light on the field of play.
- In the last 15 years Scotland has been a leading light in the field of public art and public sculpture.
- steering column
- steering committee
- steering group
- steering wheel
- steer (or take) a middle course
- steersman
- steersmanship
- steer wrestler
- steer wrestling
- steeve
- steez
- steeze
- steezy
- Stefan–Boltzmann law
- Steffens, Lincoln
- steganography
- Stegner, Wallace
- stegosaur
- stegosaurus
- Steichen, Edward
- Steiermark
- Steiger, Rod
- stein
- Steinbeck, John
- steinbock