A spur is a metal tool designed to be worn in pairs on the heels of riding boots for the purpose of directing a horse to move forward or laterally while riding. It is usually used to refine the riding aids (commands) and to back up the natural aids (the leg, seat, hands and voice). The spur is used in many equestrian disciplines. There are rules in most equestrian organizations about spur design, use and penalties for using spurs in any manner that constitutes animal abuse.

SPUR, formerly known as San Francisco Planning and Urban Renewal Association, is a non-profit research, education, and advocacy organization focused on issues of planning and governance. SPUR's history dates back to 1910, when a group of young city leaders came together to improve the quality of housing after the 1906 San Francisco earthquake and fire. That group, the San Francisco Housing Association, authored a hard-hitting report which led to the State Tenement House Act of 1911.