Verb used for the preparation of leather, esp. without tannin. Such a craftsman was known as a *'tawyer'. From the OldEngl. noun taw = an implement, the modern 'tool' is derived. Then as now, taw and tool, share the same slang reference to the male genitalia. [< OldEngl. tawian = to prepare, make ready]
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.