Editing means Reading a text which is not a translation in order to spot problematic passages, and making any needed corrections or improvements. In some cases, the text may just happen to be a translation but the editor either does not know this or does know it but treats the text as if it were not a translation.

Editors have many different duties. An editor´s daily routine will be rather different at a newspaper from what it will be at the office of a firm publishing a medical journal. The description of a particular editor´s job might include one or more of the following:
-Finding or assigning writers and handling relations with them.
-Evaluating the suitability of manuscripts and recommending changes in content, style or organization.

-Dealing with reviewers (subject-matter experts who comment on the content of specialized writing).

-Scheduling the publication process.

-Designing page layouts, with incorporation of graphics.

-Marking up manuscripts with instructions of printers.

-Obtaining permission to use copyrighted material, and dealing with other legal concerns such as libel.

-Managing the financial and material resources, and the employees, of a publishing enterprise or department.

-Amending the text submitted by a writer.
In a one-person publications department, the editor will either have to do all the above tasks – perhaps even pack and ship the final product – or else farm out tasks to freelance editors.

Another activity which is similar to editing is a regular feature of professional translation. It is often noted that translations are easier to read than their sources. That is because experienced translators of non-literary texts tend to produce translations whose writing quality is much superior to that of the source text. 

Professional editors do not apply equal editing effort to every text. In the first place, an editor may only have time to go through a particular text once, doing all four kinds of editing simultaneously, or perhaps just copyediting to eliminate the most obvious errors. Whit other texts, it may be possible to perform two or more separate edits. Additional factors are the nature of the publication and the reputation of the publisher: the editors of a scientific journal whose publisher wishes to be known internationally for readability and freedom from factual error will need to edit very carefully.