Its source gives its meaning as valiant. Though originally a given name, it is more popular and well known as a surname. The surname's first variant is O Ã³ (Raghallaigh descendent/Of Of) raghallach which was later adapted In english As'O reilly which itself has been anglicized Into. reilly
The word 'vatican' comes from Latin and is a contraction of two words in the following way: 'Vatis' = 'profetic' or 'diviner' 'Can' = 'serpent/snake'. These two words combined make: 'the profetic- or made devine serpent'. The Vatican is a place, so you may say, that 'Vatican' means 'the place of the profetic- and worshipped serpent'.
Vaticanus then is a combination of Vatic + anus, just as Romanus is a combination of Rome + anus. Therefore, vaticanus collis or vaticanus mons mean the prophetic hill or mountain , which can be rephrased as the hill or mountain of prophecy. The word Vatican is just a shortened form of the word Vaticanus, just like Claudian is a shortened form of Claudianus, as shown above.