تعریف و معنای "[have] {sth} at {one's} fingertips"

What is the origin of the idiom "have something at one's fingertips" and when to use it?

The idiom "have something at one's fingertips" originated from the literal sense of being able to physically touch something at the tips of one's fingers. In the late 1800s, references emerged to knowledge that could be "seized" or "touched" instantly, indicating thorough memorization. This drew from the metaphor of literal objects being so close as to almost touch one's fingertips. By the early 1900s, the phrase was commonly used to describe mastery making details felt like extensions of the body. It is now typically used to describe situations where an individual needs to readily access information, skills, or knowledge quickly without delays.