There are multiple origins and translations for the name Denis:
1. French, Portuguese and Slavic (Russian Денис) popular name, derived from Greek name Dionysus - "follower of Dionysus (god of wine)".
2. Comes from the Turkish word (deniz) which actually means - "sea; ocean".
Saint Denis - is a Christian martyr and Saint. In the third century, he was Bishop of Paris. He was martyred in approximately A. D. 250: after his head was chopped off, Denis is said to have picked it up and walked six miles, preaching a sermon the entire way, making him one of many cephalophores in hagiology. He is venerated in the Roman Catholic Church as patron of Paris, France and as one of the Fourteen Holy Helpers.