Kitchen, cooker, and cook look similar in spelling but refer to completely different things. A kitchen is the room itself — the space where you prepare and cook meals. A cooker is a machine inside the kitchen that has an oven and hot plates to heat and cook food. A cook is a person who prepares food, or the action of making a meal (verb). For example: 'I cook dinner in the kitchen using the cooker.' A good way to remember: a room (kitchen), a machine (cooker), a person or action (cook).
Kitchen traces back through Old English (cycene) to Latin (coquina, meaning 'a place for cooking'), which comes from the Latin verb coquere ('to cook'). The word has been used for over a thousand years to mean the room where people prepare meals.