/əkˈsɛsəri/
[noun] A thing that is added to something else to make it more useful or attractive, but is not the most important part; also, a person who helps someone else do something wrong without being the main person involved.
The word 'accessory' comes from a Latin root meaning 'to approach' — so every handbag and hair clip is, technically, something that 'came toward' you.
The story of 'accessory' begins in ancient Rome with the Latin verb *accedere*, meaning 'to approach, to come near, or to add oneself to something.' This verb was built from two parts: the prefix *ac-* (a form of *ad-*, meaning 'toward') and *cedere*, meaning 'to go' or 'to yield.' So at its most basic level, the word describes something that moves toward something else — something that joins, attaches, or adds itself to a larger whole.
From *accedere*, Latin formed the verb *accessionem* and then the Medieval Latin adjective *accessorius*, meaning 'that which is added' or 'helping.' This adjective was used in legal and scholastic writing of the Middle Ages to describe something secondary — a supporting thing, not the main thing. The idea of 'coming alongside' rather than 'leading' was built into the word from the very start.
English borrowed *accessorius* directly from Medieval Latin in the early 15th century, spelling it first as *accessorie* or *accessory*. Its earliest uses in English were almost entirely legal. A person could be an *accessory* to a crime — meaning they helped, encouraged, or failed to prevent it, but did not carry it out themselves. This legal sense preserves the original Latin idea perfectly: the accessory is the one who 'came alongside' the main act, never the act itself.
The meaning gradually expanded during the 16th and 17th centuries to include objects rather than just people. An accessory became anything that accompanied or supported a more important thing — a secondary item, an addition, a supplement. By the 18th and 19th centuries, the world of fashion had fully adopted the term, and 'accessories' became the gloves, hats, bags, and jewellery that completed an outfit without being the outfit itself. The logic is the same: they approach the main garment; they do not replace it.
It is worth noting the family of English words that share the same Latin root, *cedere* (to go). From Latin *cedere* came Old French *ceder*, and then English 'cede,' meaning to give up or yield. The same root, via Latin *procedere* → Old French *proceder* → English 'proceed'; via Latin *recedere* → Old French *receder* → English 'recede'; and via Latin *concedere* → Old French *conceder* → English 'concede.' Each of these words carries the same underlying idea of movement — going forward, going back, giving way — and 'accessory' sits quietly among them, meaning simply the thing that 'went toward' something greater than itself.