X-1

X-1 may refer to:

Aircraft

 * Bell X-1, the first aircraft to exceed the speed of sound in controlled level flight

Automobiles

 * Lada X-1, a 1981 Soviet concept MPV
 * McLaren X-1, a 2012 British one-off sports car based on the 12C

Cycles

 * Sinclair X-1, an electrically assisted faired recumbent bicycle
 * Yamaha X-1, a commuter-style motorbike

Watercraft

 * X-1 Submarine, the United States Navy's only midget submarine

Technology

 * Xbox One, a video game console
 * a one-lane PCI Express slot

Arts, entertainment, and media

 * X Minus One, a 1950s American radio show
 * X-Men (film), the first film in the X-Men franchise
 * X-One, monthly magazine produced by Imagine Publishing

Other

 * x−1, the multiplicative inverse of x (another way to denote 1⁄x, one divided by x)
 * Cygnus X-1 and Scorpius X-1, two astronomical x-ray sources
 * M82 X-1, a candidate intermediate-mass black hole detected in January 2006