American Heritage Dictionary
(6)
Century Dictionary
(18)
GNU Webster's 1913
(1)
WordNet
(2)
Elsewhere on the web
The larger loggerhead was rescued about 20 nautical miles off the coast of Tampa.— ABC7 News
"The loggerhead is eating several pounds of squid a day in addition to some crabs," said McNamara.— ABC7 News
~ / Projects / repos / loggerhead, the mirror of trunk, and a feature branch we just created.— Planet Ubuntu

American Heritage Dictionary (1)
Century Dictionary (1)
Bubble size: how much this word was used in a year
Bubble height: used more or less than expected, vs. all uses evenly distributed
You can expect to see this word about twice a year.