What does Guillermo mean?
Guillermo \gu(i)-ller-mo, guill(e)-rmo\ as a name for boys. Guillermo's name origin is Old German, and the name Guillermo means "determined protector". Guillermo is a form of Guillaume (Old German): French variant of William.
Guillermo▼ has 36 related variations via Guillaume, William: Bill▼, Bille, Billie▼, Billy▼, Gillermo, Guglielmo, Guilherme, Gwillyn, Gwilym, Liam, Vilhelm, Villem, Wilek, Wiley▼, Wilhelm▼, Wilhelmus, Wilkes, Wilkie, Wilkinson, Will▼, Willem, Willhelmus, Willi, Williams▼, Williamson, Willie▼, Willis▼, Willkie, Wills, Willson, Willy, Wilmer▼, Wilmot, Wilmott, Wilson▼ and Wim.
Guillermo is a very prominent first name for men (#379 out of 1220, Top 31%) and also a very prominent last name for both adults and children (#11647 out of 150436, Top 8%). (2000 U.S. Census)
Displayed below is the birth name popularity of Guillermo for boys. Guillermo was first listed in 1900-1909 and reached its apex rank of #352 in the U.S. in the year 1996, and is at #678 currently. (Top 1000 Birth Names Statistics, 2014)
Popular variation forms of Guillermo (#678 in 2014) are Liam (#2 in 2014), William (#5), Wilson (#594), Willie (#722), Will (#763), Billy (#794), Willy, Wilmer, Billie, Willis, Wilhelm, Wiley, Williams and Bill. Usage of these boy names was at its highest during 1920-1929 (usage of 0.5873%) and is now significantly lower (usage 0.2295%, down 60.9%), with versions such as Billy, Will, Guillermo, Willie and Wilson falling out of style. Liam (#2) is the most contemporarily stylish baby name among these. Displayed below is a comparison of the popularity of Guillermo and related names. (Top 1000 Birth Names Statistics, 2014)