Lookups spiked on July 24, 2013.
It saw plenty of use surrounding the announcement of the Royal Baby's name.
For example, as the Irish Times reported,
"George was the most popular name with the bookies with betting firms William Hill, Coral and Paddy Power all offering short odds on the moniker."
Meaning "name" or "nickname," moniker is sometimes used simply to avoid repeating name too much.
It probably comes from a modification of ainm, the Irish word that means "name."