cahier

the word 'cahier' entered english directly from french, retaining its original spelling and core meaning of a notebook or booklet. its lineage traces back to the latin 'quaterni', denoting a set of four, which evolved in vulgar latin to mean a gathering of four sheets of parchment folded together to form a small book. this concrete sense of a physical gathering of pages broadened in old french to mean any notebook or report. the english adoption in the 19th century preserved this specialized sense, often referring to a formal report or, more specifically, the iconic exercise books used in french schools.

this word is a direct loanword from french and is not productively segmented using english morphemes. in its source language, it derives from old french 'quaier', meaning 'a gathering of sheets', which itself comes from latin 'quaterni', meaning 'set of four' (from 'quattuor', four), referring to sheets folded in four.