A trestle (sometimes tressel) is a rigid frame used as a support, historically a tripod used both as stools and to support tables at banquets, and in contemporary usage usually referring to a bridge composed of a number of short spans supported by such frames. In the context of trestle bridges, each supporting frame is generally referred to as a bent. Timber and iron trestles were extensively used in the 19th century, the former making up from 1 to 3% of the total length of the average railroad. In the 21st century, steel and sometimes concrete trestles are commonly used to bridge particularly deep valleys while timber trestles remain common in certain areas. The historical trestle is sometimes seen as a charge in heraldry.

ATLAS-I (Air Force Weapons Lab Transmission-Line Aircraft Simulator), better known as Trestle, was the codename for a unique electromagnetic pulse (EMP) generation and testing apparatus built between 1972 and 1980 during the Cold War at Sandia National Laboratories near Kirtland Air Force Base in Albuquerque, New Mexico.