A chef is a person who cooks professionally for other people

People

People is a plurality of human beings or other beings possessing enough qualities constituting personhood. It has two usages:* as the plural of person or a group of people People is a plurality of human beings or other beings possessing enough qualities constituting personhood. It has two usages:*...

. Although over time the term has come to describe any person who cooks for a living, traditionally it refers to a highly skilled professional who is proficient in all aspects of food preparation.
The word "chef" is borrowed (and shortened) from the French

French language

French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

 term chef de cuisine, the director or head of a kitchen

Kitchen

A kitchen is a room or part of a room used for cooking and food preparation.In the West, a modern residential kitchen is typically equipped with a stove, a sink with hot and cold running water, a refrigerator and kitchen cabinets arranged according to a modular design. Many households have a...

. (The French word comes from Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 caput and is cognate

Cognate

In linguistics, cognates are words that have a common etymological origin. This learned term derives from the Latin cognatus . Cognates within the same language are called doublets. Strictly speaking, loanwords from another language are usually not meant by the term, e.g...

 with English

English language

English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...

 "chief".) In English, the title "chef" in the culinary profession originated in the haute cuisine

Haute cuisine

Haute cuisine or grande cuisine was characterised by French cuisine in elaborate preparations and presentations served in small and numerous courses that were produced by large and hierarchical staffs at the grand restaurants and hotels of Europe.The 17th century chef and writer La Varenne...

of the 19th century.