Multiplayer. First-person perspective. Downloadable content. Some game features are easily defined by a short word or phrase, and their meanings are universally accepted and understood. But the definitions of some features are much more nebulous, even when those terms are used nearly as much.
One such word is "polish." Between reviews praising a "highly polished experience" to news of a game being "delayed for additional polish," "polish" is a word that gets thrown around a lot in the gaming industry, despite a lack of consensus on what it actually means.