What is "transient"

Transient \Tran"sient\, n. That which remains but for a brief time.
--Glanvill.

Transient \Tran"sient\, a. [L. transiens, -entis, p. pr. of transire, transitum, to go or pass over. See Trance.]

1. Passing before the sight or perception, or, as it were, moving over or across a space or scene viewed, and then disappearing; hence, of short duration; not permanent; not lasting or durable; not stationary; passing; fleeting; brief; transitory; as, transient pleasure. ``Measured this transient world.''
   --Milton.

2. Hasty; momentary; imperfect; brief; as, a transient view of a landscape.

3. Staying for a short time; not regular or permanent; as, a transient guest; transient boarders. [Colloq. U. S.]

   Syn: Transient, Transitory, Fleeting.

   Usage: Transient represents a thing as brief at the best; transitory, as liable at any moment to pass away. Fleeting goes further, and represents it as in the act of taking its flight. Life is transient; its joys are transitory; its hours are fleeting.

   What is loose love? A transient gust.
   --Pope

   If [we love] transitory things, which soon decay, Age must be loveliest at the latest day.
   --Donne.

   O fleeting joys Of Paradise, dear bought with lasting woes.
   --Milton. [1913 Webster] -- Tran"sient*ly, adv. -- Tran"sient*ness, n.

c.1600, "transitory, not durable," from Latin transientem (nominative transiens) "passing over or away," present participle of transire "cross over, go over, pass over, hasten over, pass away," from trans- "across" (see trans-) + ire "to go" (see ion). Meaning "passing through a place without staying" is from 1680s. The noun is first attested 1650s; specific sense of "transient guest or boarder" attested from 1857. Related: Transiently.

a. 1 Passing or disappearing with time; transitory. 2 Remaining for only a brief time. 3 (context physics English) decay with time, especially exponentially. 4 (context mathematics stochastic processes of a state English) having a positive probability of being left and never being visited again. 5 Occasional; isolated; one-off; individual. 6 Passing through; passing from one person to another. 7 (context philosophy English) Operating beyond itself; having an external effect. n. 1 Something which is transient. 2 (context physics English) A transient phenomenon, especially an electric current; a very brief surge. 3 (context acoustics English) A relatively loud, non-repeating signal in an audio waveform which occurs very quickly, such as the attack of a snare drum. 4 A person who passes through a place for a short time; a traveller; a migrant worker 5 An unhoused person

1. adj. of a mental act; causing effects outside the mind [syn: transeunt] [ant: immanent]

2. enduring a very short time; "the ephemeral joys of childhood"; "a passing fancy"; "youth's transient beauty"; "love is transitory but at is eternal"; "fugacious blossoms" [syn: ephemeral, passing, short-lived, transitory, fugacious]

1. n. one who stays for only a short time; "transient laborers"

2. (physics) a short-lived oscillation in a system caused by a sudden change of voltage or current or load

A transient event is a short-lived burst of energy in a system caused by a sudden change of state.

The source of the transient energy may be an internal event or a nearby event. The energy then couples to other parts of the system, typically appearing as a short burst of oscillation.

In acoustics and audio, a transient is a high amplitude, short-duration sound at the beginning of a waveform that occurs in phenomena such as musical sounds, noises or speech. It can sometimes contain a high degree of non-periodic components and a higher magnitude of high frequencies than the harmonic content of that sound. Transients do not necessarily directly depend on the frequency of the tone they initiate.

Transients are more difficult to encode with many audio compression algorithms, causing pre-echo.

In civil engineering, a transient is used to refer to any pressure wave that is short lived (i.e. not static pressure or pressure differential due to friction/minor loss in flow). The most common occurrence of this is called water hammer. In a pipe network, when a valve or pump is suddenly shut off, the water flowing in an adjacent pipe is suddenly forced to stop. A region of high pressure builds up immediately behind said valve or pump and a region of low pressure forms in front of it. The momentum of the water is suddenly transferred into the fitting and Newton's Third Law kicks in forming growing the high-pressure region of water as it all "piles up" in the pipe. This high pressure region then travels back along the pipe in the form of a wave. The border of the high-pressure zone is referred to as a pressure wave, or transient (which is apt as the general definition of a transient is something that only exists for a short period of time).

Transients are often misunderstood and not accounted for in the design of water distribution systems and are often the cause of (or a contributing factor to) hydraulic element failures (i.e. pipe breaks, pump/valve failures, etc.).

In computer programming, transient is a property of any element in the system that is temporary. The term applies to transient applications, i.e. software for the end-user which is displayed with a transient application posture; transient data, which is discarded after it is no longer needed by the computation; and transient code which are subroutines or software components that are loaded in the system only for a fraction of the total run time.

Examples of applications of the term are described below.