Language always is in a slow transition where spelling, pronunciation, definitions, and – more glacially –the grammar itself, is concerned. The competing spellings of co-worker and coworker is among those words in our language now undergoing just such a change.
Traditionally, co-worker is considered correct. As the Associated Press Stylebook still notes, typically words that denote position or occupation require a hyphen. Such words include co-author, co-owner and co-star.
The Chicago Manual of Styles 16th edition, however, lists coworker as not requiring a hyphen, a change from its 15th edition which allowed for either spelling. From personal experience as an editor, I’ve increasingly noticed writers using coworker without a hyphen, suggesting the 16th edition’s influence on writing and publishing.
Bottom Line: Use the style that your publisher prefers – if writing a magazine or newspaper article, that likely means AP style; if writing a book, that likely means Chicago Manual – and be internally consistent by always using the same style throughout your manuscript.
Need an editor? Having your book, business document or academic paper proofread or edited before submitting it can prove invaluable. In an economic climate where you face heavy competition, your writing needs a second eye to give you the edge. Whether you come from a big city like New York, New York, or a small town like Bantam, Connecticut, I can provide that second eye.