/ˈæbətwɑːr/
[noun] A place where animals are killed and prepared for use as food; a slaughterhouse. The word is often used in more formal or official contexts instead of the simpler word 'slaughterhouse'.
The word 'abattoir' comes from a French verb meaning 'to beat down' — the same root that gives us 'abate' and 'batter'.
The word 'abattoir' entered English from French in the early 19th century, around 1820, at a time when British cities were growing rapidly and public health reformers were pushing for organised, contained facilities for animal slaughter. Before then, animals were often killed in open streets and markets, and the mess and smell were considered a serious urban problem. The French word arrived along with the concept of regulated slaughterhouses, which France had begun establishing under Napoleon's reforms.
The French word 'abattoir' comes from the verb 'abattre', meaning 'to strike down', 'to knock down', or 'to fell'. This verb is built from the prefix 'a-' (from Latin 'ad-', meaning 'to' or 'towards') and 'battre', meaning 'to beat' or 'to strike'. 'Battre' itself descends from the Vulgar Latin 'battere', a variant of classical Latin 'batuere', meaning 'to beat'. So at its heart, 'abattoir' is quite literally a place where things are beaten down.
This Latin root 'batuere' is surprisingly productive in English. It passed into Old French as 'battre', and from there gave English several familiar words. Old French 'battre' → English 'batter' (to strike repeatedly). The same root produced Old French 'bataille' → English 'battle'. It also gave us 'bat' (the striking implement) and 'combat', via Old French 'combatre' (from Latin 'com-' plus 'batuere'). Even the word 'abate' — meaning to reduce or lessen — shares this ancestry, coming from Old French 'abatre' in the sense of beating something down or reducing its force.
The suffix '-oir' in French is equivalent to the English '-ory' or '-er' — it marks a place where an action happens or a tool used for an action. So 'abattoir' literally means 'a place for beating down' or 'a place of felling'. French uses this suffix widely: 'lavoir' is a place for washing, 'couloir' is a channel or corridor (from 'couler', to flow). English borrowed 'couloir' directly in the context of mountain gullies, and 'reservoir' follows the same pattern.
Interestingly, English had its own perfectly good word for the concept — 'slaughterhouse' — dating back to the 16th century. But 'abattoir' was adopted partly because it sounded more clinical and neutral, distancing official language from the blunt reality of killing. This tendency to borrow French words to soften or professionalise a concept is very common in English: we say 'beef' instead of 'cow meat', 'pork' instead of 'pig meat', a pattern also introduced by French-speaking Normans after 1066. 'Abattoir' fits neatly into this long tradition of French lending English a polite veil over uncomfortable truths.