Ioannes or Iohannes.
If you are thinking of the male christian name associated with John, then the Latin is Jacobus
I guess you mean the genitive of the Latin form of the name John (Iohannes); it is Iohannis, later spelled Johannis.
The name Joannes is Latin for John, or Janusz in Polish. In the Middle Ages, scholarly works were written in Latin, so the authors gave their names in Latin.
Johannes, Johannis, m: John (3rd declension)
The name John is derived, via Latin and Greek, from the Hebrew name Yochanan (יוחנן) meaning "The Lord is gracious". (:
Juan is Spanish for "John", and the medieval or Low Latin word would be Iohannes. Since the name did not exist in ancient times, there is no Classical Latin version of that name.
Hypericum perforatum.
Iohannes in Latin. Both Ioannis and Iannis are the Greek forms of John.
The English name "John" (and French "Jean", Irish "Seán", Russian "Ivan" and many others) comes from the Latin name spelled Johannes or Joannes (or Iohannes/Ioannes: 'j' and consonantal 'i', both pronounced like English 'y', are interchangeable in Latin spelling). This in turn came from the Hebrew name Yohanan, "God has favored".
John is the English form of the Latin Iohannes which is derived from the Greek Ιωαννης (Ioannes).The Greek is derived from the Hebrew name יוֹחָנָן(Yochanan) meaning "Yahweh is gracious".
Hermes' Latin name was mercury.
the latin name for crocodile is 'crocodilius'!! =P