Editor

Editor has four major senses:

a person responsible in some way for the final appearance of a publication;
a film editor, a person responsible for the flow of a motion picture or television program from scene to scene
a sound editor, a person responsible for the flow and choice of music, voice, and other sound material in a recording
an editor (software), a software tool that can be used to input and format text.

According to the Oxford English Dictionary, editor comes from the Latin phrase e ditus which means "to put forward". The editor ludorum in Ancient Rome was the person who put on the games. In French, editeur means "publisher". The word came into English from French. The verb edit is a back formation from editor.

Human editors in the print publishing industry include people who are responsible for:

obtaining copy or recruiting authors, such as the acquisitions editor for a publishing house
writing or obtaining material for a section of a newspaper, for example, contributing editor, book reviews editor, travel editor
organizing and publishing a magazine — an editor-in-chief
organizing and managing contributions to a multi-author book, for example, a symposium editor
producing a definitive edition of a classic author's works — a scholarly editor
improving an author's writing so that they indeed say what they want to say, in an effective manner — substantive editor. Depending on the writer's skill, this editing can sometimes turn into ghost writing.
correcting spelling, grammar, and matters of house style — a copy editor
choosing the layout of the publication and communicating with the printer — a production editor
functioning like the guy who follows the elephants in a parade — a Wikipedia editor

The smaller the publication, the more these roles run together. In particular, the substantive editor and copy editor often overlap:

fact checking can be the responsibility of either
the copy editor who finds an inappropriate term or phrase will often suggest an improvement