/ˈmænjuəl/
[adjective] Done with the hands, or relating to physical work rather than machines or computers. It can also be used as a noun to mean a book of instructions that explains how something works.
Every time you pick up an instruction booklet, you are literally holding a 'handful' of knowledge — that is exactly what the word once meant.
The story of 'manual' begins with one of the most ancient and universal parts of the human body: the hand. The Latin word 'manus', meaning 'hand', sits at the very heart of this word. 'Manus' was itself descended from Proto-Indo-European roots connected to the hand and its ability to grasp, and it was one of the most productive roots in the entire Latin language — giving rise to dozens of words that Romans used every single day.
From 'manus', Latin speakers formed the adjective 'manualis', which simply meant 'of or belonging to the hand' or 'that which fits in the hand'. The Romans used this word in very practical, physical ways — a 'manualis' thing was something you could hold, carry, or operate with your hands. There was nothing abstract or metaphorical about it. It was grounded entirely in the physical experience of working with one's hands.
The word passed into Old French as 'manuel', carrying much the same meaning, before crossing the Channel into Middle English in the 15th century. English writers first used it as an adjective to describe tasks done by hand, particularly in contrast to work done by animals or machines — though machines at that time were far simpler than they are today. The word felt fresh and useful in English because it captured a distinction that was becoming increasingly important as society grew more complex.
Interestingly, the noun sense of 'manual' — meaning a small handbook or guide — also developed from the idea of something held in the hand. A 'manual' was originally a book small enough to be held comfortably while reading, the kind you could carry with you and consult easily. This is a lovely example of how physical experience shapes language: the format of the object gave its name to the object itself.
The Latin root 'manus' also gave English a remarkable family of related words. Through Latin 'manufactor' (one who makes by hand), we get 'manufacture'; through Latin 'manu scriptus' (written by hand), we get 'manuscript'; through Latin 'manipulus' (a handful), we get 'manipulate'. Even 'manage' traces back through Italian 'maneggiare' (to handle, especially a horse) → French 'manège' → English 'manage', all from the same Latin 'manus'. The hand, it turns out, has left its fingerprints all over the English language.