Assistant, Helper, Coadjutor, Aid, Aide and Aide-de-camp all denote persons who take over part of the duties of another, especially in a subordinate capacity.
Assistant is applicable to a person who meets this description, regardless of the status of his work.
- a baker's assistant
- a bishop's assistant
- a superintendent's assistant
Helper often implies apprenticeship in a trade or the status of an unskilled laborer.
- a bricklayer's helper
- a mother's helper often performs the duties of a nursemaid
Coadjutor usually implies equivalence except in authority; it may be used either of a co-worker or a volunteer assistant.
- in working so complex a mechanism as the government of the empire he must have willing coadjutors
- at St. James I met with a kind and cordial coadjutor in my biblical labors in the bookseller of the place
- decided to share the government of the Roman world with a coadjutor
—R. M. French
In a specific use it names or is applied to a bishop who serves as an assistant to the bishop having jurisdiction over a diocese. Especially in Roman Catholic and Protestant Episcopal use it implies the right of succession.
Aid and aide are often interchangeable synonyms of assistant.
- a laboratory aid
- aides and orderlies . . . assist the professional nurses
Aide frequently but aid rarely denotes a special and often highly qualified assistant able to act as an adviser to his principal.
- questioned the use of presidential aides in foreign affairs
- with their chief aides they will discuss the problems of the interregnum
Aide and aide-de-camp designate a military or naval officer who personally attends a general or a sovereign, a president or a governor, often as an escort but sometimes with definitely prescribed duties.