2S

2S or 2s may refer to:

Science

 * 2s electron in an atomic orbital
 * 2S, a protein-folding intermediate with two disulphide bonds

Transportation

 * 2S gondola lift
 * 2S, a series of Toyota S engines
 * Birdman Chinook 2S, ultralight aircraft
 * Southwind Airlines (IATA code), a Turkish airline

Other uses

 * Two-spirit, a term used by some indigenous North Americans to describe certain people in their communities who fulfill a traditional third-gender (or other gender-variant) ceremonial role in their cultures
 * IIS, a draft status abbreviation for conscription into the United States armed forces