clavis

noun

1. A Roman key.

   “Iron clavis, the solid web-shaped at the edges to fit the wards in the lock, and having a pointed broach and a kite-formed looped haft.”

2. A device for restraint of the hands.

   “His hands were restrained by means of a clavis and bolt (of iron), appropriated to each wrist, and united by a padlock.”

3. Synonym of glossary: a key to the meaning of various terms.

   “Homer, with a clavis, I have had possession of some years.”

4. A key; an identification guide; a series of logically organized groups of discriminating information which aims to allow the user to correctly identify a taxon.

   “There are many disadvantages in using a clavis intended for another country, which necessarily includes plants that are absent from our islands while it omits some that are present and neglects the peculiarities of our island flora.”