-th²

Forming nouns.

Old English ‑thu, ‑tho, ‑th.

Some have been formed from verbs: berth (from bear), growth (from grow), and stealth (from steal). Others derive from adjectives: breadth (from obsolete brede, related to broad), depth (from deep), health (from a Germanic stem related to whole), truth (from true), and width (from wide). Though the ending is not currently active, one example that has returned from obscurity in the latter part of the twentieth century is coolth, coolness; another often found is the obsolete heighth, a mis-spelling of height on the pattern of these others.