Mojito is derived from the Spanish mojo sauce, which often contains lime juice (see "mojito" at Dictionary.com, citing the American Heritage Dictionary of the English Language, Fourth Edition, 2006, Houghton Mifflin), while mojo is derived from the Spanish verb mojar, meaning "to make wet" (see definition 3 of "mojo" at Dictionary.com, citing Webster's New Millennium Dictionary of English, Preview Edition (v 0.9.7), 2003–2007, Lexico Publishing Group, LLC)
