Oxford Dictionary of English Idioms (3rd edition)

This dictionary is clearly laid out, with the main noun or verb in a phrase usually providing the keyword for the idiom: “of a certain age” comes under Age, for example, and there are more cross‐references in this third edition, so Certain redirects you to Age. There is also a thematic index with headings such as Anxiety and Worry, Argument and Conflict and Chaos and Disorder; our example comes under Age, alongside “out of the Ark”, “seen better days”, “no spring chicken”, etc. Many entries include items of extra information: for example, “of a certain age” was first recorded in...