
1) Adjective in the Marine motto 2) Faithful to Caesar 3) Latin boy name
Found on
https://www.crosswordclues.com/clue/fidelis

Latin, meaning: faithful, loyal, true
Found on
http://archives.nd.edu/fff.htm
[bishop of Mérida] Fidelis was the Bishop of Mérida flourishing probably in the 550s and 560s. Fidelis was a Greek who was hired out by his parents to a merchant venture to Spain in the mid sixth century, arriving in Mérida, where his mother`s brother, Paul, was bishop. As it was customary of merchants to greet the bishop with gifts upon...
Found on
http://en.wikipedia.org/wiki/Fidelis_(bishop_of_Mérida)

Loyal.
Found on
http://www.encyclo.co.uk/local/20764

(Latin) loyal, faithful.
Found on
https://www.encyclo.co.uk/local/10135

faithful, loyal, true
Found on
https://www.math.ubc.ca/~cass/frivs/latin/latin-dict-full.html
No exact match found.