Yep, "Defender of the Faith". Originally a title bestowed by the Pope on King Henry VIII for openly opposing the Reformation. When Henry went Protestant himself, he and his descendants continued to use the title, to signify their headship of the Church of England.
It also appears on Australian predecimal coins, normally abbreviated as "F:D:". I believe Australia and Britain were the only countries in the Empire/Commonwealth to routinely include this title on the coins. Early series Australian coins of Elizabeth II are known as "Godless coins" because the Mint forgot to include "F:D:" in the titles.
