(abbreviated 3ϕ) a common type of alternating current used in electricity generation, transmission, and distribution.

In electrical engineering, three-phase electric power systems have at least three conductors carrying alternating voltages that are offset in time by one-third of the period.

In computer networking and distributed databases, the three-phase commit protocol is a distributed algorithm that ensures all nodes in a system agree to commit or abort a transaction.

a theory of traffic flow developed by Boris Kerner between 1996 and 2002.

used in Italy, Switzerland and the United States in the early twentieth century.