Chief
Chief (or jefe in the Spanish language) was a common designation for leading officers and enlisted personnel aboard Federation starships and installations. 

When used as a title referring to an officer it denoted a member of positional authority, such as a staff officer, or department head status. 

In reference to an enlisted person, it referred directly to rank. ()

Titles 
 Chief Archon, a Cardassian judge
 Chief astronomer
 Chief city administrator
 Chief conn officer, the primary helmsman/navigator of a starship
 Chief cosmetics officer
 Chief delegate
 Chief engineering officer/chief engineer, head of the engineering department on a starship
 Assistant chief engineer, second-in-command of the engineering department on a starship
 Chief Examiner
 Chief exobiology specialist
 Chief financial officer, a senior position in the Ferengi Alliance
 Chief geologist, head of the geology department on a starship
 Chief inspector/chief investigator
Chief medic
 Chief medical officer/chief surgeon, head of the medical department on a starship
Chief morale officer
Chief of Medicine
 Chief of mining operations
 Chief of operations, head of the operations division
 Chief of staff
 Chief of Starfleet Intelligence, in charge of Starfleet Intelligence
 Deputy Chief of Starfleet Intelligence
 Chief of Starfleet Operations, in charge of Starfleet Operations
 Chief of Starfleet Security
 Chief of surgery
 Chief officer
 Chief processing engineer
 Chief scientist
 Chief security officer/Chief of security/security chief/head of security, in charge of security on a starship or at a Starfleet facility
 Chief tactical officer, in charge of tactical stations on a starship
 Chief thanatologist
 Commander in chief, in charge of Starfleet/president
 Section chief, head of a section on Starfleet vessels
 Transporter chief, in charge of transporter operation

Ranks 
 Chief petty officer, rank given to senior non-commissioned officers, who have substantial experience and are considered experts in their specific profession.
 Senior chief petty officer, a rank superior to chief petty officers and subordinate to master chief petty officers.
 Master chief petty officer, highest enlisted rank, often given a great amount of responsibility and leadership roles, while subordinate to commissioned officers.

cs:Šéf
de:Chief
ja:チーフ
nl:Chief
Titles