/əˈtaɪər/
[noun] The clothes that a person is wearing, especially formal or special clothing. It can also be used as a verb meaning to dress someone in a particular way.
The word 'attire' originally meant to arrange or put things in a row — dressing was just one kind of ordering.
The word 'attire' reaches us from Old French, where the verb 'atirer' meant to put in order, to arrange, or to draw into a line. This was built from the prefix 'a-' (meaning 'toward') and 'tire', which referred to a row, a rank, or a sequence of things arranged neatly together. The underlying idea was not clothing at all — it was the concept of bringing things into an orderly arrangement.
The Old French 'tire' is also related to the Old French verb 'tirer', meaning to pull or draw, which suggests the original image was of pulling things into alignment, as a soldier might arrange troops in a row. This same root 'tirer' went on to give English words like 'tirade' — originally a long, drawn-out volley of speech — through the path Old French 'tirer' → 'tirade' → English 'tirade'.
When the word crossed into Middle English in the 13th and 14th centuries, it arrived carrying both meanings — to put in order generally, and to dress or equip someone. By the time it settled fully into English, the clothing sense had won out almost entirely. To 'attire' someone was to arrange their garments upon them, a process that in the medieval world was a careful, deliberate act — clothing was layered, fastened, and adjusted with considerable effort.
The noun sense — attire as the clothing itself — followed naturally. By the late Middle English period, 'attire' had shifted from describing the act of dressing to describing the outfit that resulted. This is a common pattern in English: a verb describing a process gradually becomes a noun describing the product of that process.
What makes 'attire' particularly interesting is the elevated register it has always carried. Even in its earliest English uses, it tended to refer to fine or ceremonial clothing rather than everyday wear. A peasant wore clothes; a knight wore attire. This sense of formality and grandeur has never really left the word — today, hotel invitations specify 'formal attire', and wedding announcements describe the 'bridal attire', keeping alive that original medieval sense of clothing as something carefully arranged and presented.