What’s the difference between analog and digital, and why is the latter word, which originally referred to fingers, now the antithesis of “hands-on”?
An analog is something related to physical quantities (hence the name; analog comes from a Greek word meaning “proportion”): An analog clock, for example, shows the passage of time by measuring it with a “hand” that pivots on a central axis, while a measuring tape represents the length of a tangible phenomenon such as a room’s dimensions.
By contrast, digital refers to a device’s reading of binary units, zeros and ones, to perform functions and to the storage of information as binary units rather than an analog recording medium such as magnetic ribbon. Ironically, however, digit stems from the Latin term digitus, meaning “finger” or “toe.” The path from appendages to algorithms involves the use of fingers to count, thus the extension of the definition of digit to “number below ten.” The use of zeros and tens as the basis of the on-off duality of binary computer systems led the technology to be referred to as digital technology.
Indeed, the word bit, referring to the basic unit of digital information, is a contraction of the phrase “binary digit.”
The adjective digital now refers both to something done or having to do with fingers (for example, “digital manipulation”) and something related to digitally rendered numbers, or to computerized data or to electronics. Two other terms with the same root word are digitalis, referring to a plant popularly known as the foxglove and to a medicine extracted from it, and prestidigitation, a sesquipedalian synonym for magic.
Digitalis is a Latinized form of the German word fingerhut (“thimble”), because of the resemblance of the plant’s flowers to the sewing implement. Prestidigitation, meanwhile, is another Latin-looking invention influenced by prestige, which comes from the Latin word praestigiae, “juggler’s tricks.” (Prestige acquired a laudatory meaning and connotation only in the early twentieth century.) It’s a combination of the Italian word presto and digit — hence, “quick fingers.”
Analog, meanwhile, calls to mind its full-form predecessor analogue (which spelling for the adjectival form is also preferred in British English), which means “something similar.” An analogy is also a similarity, or it can refer to a correspondence or to another form of comparison. Analogous is the adjectival form.