1. n. [Geology]

A surface of breakage, cracking or separation within a rock along which there has been no movement parallel to the defining plane. The usage by some authors can be more specific: When walls of a fracture have moved only normal to each other, the fracture is called a joint.

See related terms: fault,  fracture

2. n. [Drilling]

A length of pipe, usually referring to drillpipe, casing or tubing. While there are different standard lengths, the most common drillpipe joint length is around 30 ft [9 m]. For casing, the most common length of a joint is 40 ft [12 m].

See related terms: casing,  casing string,  connection,  drillpipe,  kelly down,  make a connection