frank1 / frangk/ • adj. open, honest, and direct in speech or writing, esp. when dealing with unpalatable matters: a long and frank discussion to be perfectly frank, I don't know. ∎ open, sincere, or undisguised in manner or appearance: Katherine saw her look at Sam with frank admiration. ∎ Med. unmistakable; obvious: frank ulceration.DERIVATIVES: frank·ness n.frank2 • v. [tr.] (often be franked) stamp an official mark on (a letter or parcel), esp. to indicate that postage has been paid or does not need to be paid. ∎ hist. sign (a letter or parcel) to ensure delivery free of charge. ∎ archaic facilitate or pay the passage of (someone): English will frank the traveler through most of North America. • n. an official mark or signature on a letter or parcel, esp. to indicate that postage has been paid or does not need to be paid.DERIVATIVES: frank·er n.frank3 • n. short for frankfurter.
The name is recorded from Old English (in form Franca) and is of Germanic origin, perhaps from the name of a weapon and related to Old English franca ‘javelin’; it is ultimately related to France and French.
Hence (from the sense †‘free of charge’ of the adj.) vb. superscribe (a letter, etc.) with one's signature to ensure free conveyance, (hence) stamp XVIII; facilitate the passage of XIX.