Eatery is a colloquial American formation from eat + -ery (as in bakery, brewery), first recorded in the early 20th century. The ancestry passes through Old English etan, Proto-Germanic *etaną, and Proto-Indo-European *h₁ed-. The suffix -er marks an agent, instrument, or associated person, so the English form is shaped by recognizable word formation as well as by its inherited or borrowed base. In present use as a noun, it means "an informal restaurant or place to eat", keeping the historical formation close to the word's ordinary semantic work. Its colloquial history matters: the word belongs to informal usage before settling into the present dictionary sense. Related words include eat, eats, and eatable.