A profession is a field of work that has been successfully professionalized. It can be defined as a disciplined group of individuals, professionals, who adhere to ethical standards and who hold themselves out as, and are accepted by the public as possessing special knowledge and skills in a widely recognised body of learning derived from research, education and training at a high level, and who are prepared to apply this knowledge and exercise these skills in the interest of others.

Professional occupations are founded upon specialized educational training, the purpose of which is to supply disinterested objective counsel and service to others, for a direct and definite compensation, wholly apart from expectation of other business gain. Medieval and early modern tradition recognized only three professions: divinity, medicine, and law, which were called the learned professions. A profession is not a trade and not an industry.

Some professions change slightly in status and power, but their prestige generally remains stable over time, even if the profession begins to have more required study and formal education. Disciplines formalized more recently, such as architecture, now have equally long periods of study associated with them.

Although professions may enjoy relatively high status and public prestige, not all professionals earn high salaries, and even within specific professions there exist significant differences in salary. In law, for example, a corporate defense lawyer working on an hourly basis may earn several times what a prosecutor or public defender earns.