The English idiomatic phrase, “in a tick,” refers to something happening in a very short amount of time. A tick is a short length of time, shorter than a second. Definitions vary on the actual amount of time that is represented by this informal word.
In the scientific realm, where it is sometimes used, a tick can mean a nanosecond or 100 nanoseconds. Its use varies, and must be specifically stated by the parties who are using it to describe time. In other industries, such as in the timing of athletic activities, the tick is usually referred to as one tenth of a second. In computer programming, it refers to an often arbitrary length of time recognized by a digital timer.
When English speakers say something will be done, “in a tick,” they are saying that it will be done quickly. Many other idioms in English exist to express the same idea. For example, English speakers might also say “in a jiffy,” or use an abbreviated version of the word “second” as in, “in a sec.” Another more idiomatic phrase is, “in two shakes of a lambs tail.”
The origin of the phrase, “in a tick,” is somewhat unclear. Many word historians assert that the phrase was originally based on the ticking of a clock. English speakers might also refer to, “the ticking of time,” or use the word tick as a verb in many other ways.
The idiomatic phrase, “in a tick,” is most commonly used to describe an activity or event. Rarely will English speakers say, “will you have it done in a tick?” or use the phrase in question form. In this way, the phrase is similar to the others mentioned above. These phrases are most often used as a reassurance to someone who wants to know how soon something will be done. For example, in response to questions like “when will you have my car ready?” a proper answer would be “in a tick.”
Those not familiar with the phrase should not confuse it with others based on the word, “tick,” as well as the associated idiomatic word “tock.” Together, “tick-tock” describes the sound of a clock. English speakers might talk about, “time tick-tocking away,” or “the tick-tock of time,” without really referring to any specific unit of time. Some English speakers might also use the phrase, “tick when I should tock,” which generally refers to less productive or less achieving behavior.