Editing Latency (engineering) (section)

{{Short description|Time interval between an input and a response}}
{{more citations needed|date=April 2011}}
{{Use American English|date=September 2019}}

'''Latency''', from a general point of view, is a time delay between the [[Causality|cause and the effect]] of some physical change in the [[system]] being observed. [[Lag (video games)|Lag]], as it is known in [[Gaming culture|gaming circles]], refers to the latency between the input to a simulation and the visual or auditory response, often occurring because of [[network delay]] in online games.<ref>[https://www.hackapedia.com/terms/l/latency "Latency"] {{Webarchive|url=https://web.archive.org/web/20210422025642/https://hackapedia.com/terms/l/latency |date=2021-04-22 }} Retrieved 2020-10-27.</ref> The original meaning of “latency”, as used widely in psychology, medicine and most other disciplines, derives from “latent”, a word of Latin origin meaning “hidden”.<ref>https://www.etymonline.com/word/latent</ref>  Its different and relatively recent meaning (this topic) of “lateness” or “delay” appears to derive from its superficial similarity to the word “late”, from the old English “laet”.<ref>https://www.etymonline.com/word/late</ref>

Latency is physically a consequence of the limited velocity at which any [[Event (relativity)|physical interaction]] can propagate. The magnitude of this velocity is always less than or equal to the [[speed of light]]. Therefore, every physical system with any physical separation (distance) between cause and effect will experience some sort of latency, regardless of the nature of the stimulation to which it has been exposed.

The precise definition of latency depends on the system being observed or the nature of the simulation. In [[Telecommunications|communications]], the lower limit of latency is determined by the [[Transmission medium|medium]] being used to transfer information. In [[Reliability (computer networking)|reliable]] two-way communication systems, latency limits the maximum rate at which information can be transmitted, as there is often a limit on the amount of [[Data in transit|information that is in-flight]] at any given moment. Perceptible latency has a strong effect on [[user satisfaction]] and [[usability]] in the field of [[human–machine interaction]].<ref>{{cite web |last= Souders |first= Steve |title=Velocity and the Bottom Line |url=http://radar.oreilly.com/2009/07/velocity-making-your-site-fast.html |access-date=23 February 2023}}</ref>