code [ME] This was originally a term for a system of laws; the sense ‘secret writing’ developed in the early 19th century from the use of flags for signals in the navy. The computing sense dates from the 1940s. Code comes from Latin codex, which developed from a simple meaning of a ‘a block of wood’ to ‘a block split into leaves or tablets’, thus ‘a book’, and entered English in the late 16th century. The related term codicil [LME] is from Latin codicillus, a diminutive of codex, and thus applies to a ‘small’ part of a legal document.