This is the 1740th most frequent Spanish word.
guillermo
"Guillermo" is the Spanish form of the name "William."
Here, 'Guillermo' is used as a proper noun, referring to a person's name.
Guillermo es un nombre común en español.
Guillermo is a common name in Spanish.
In this sentence, 'Guillermo' is used to refer to the translation of the name 'William' when referring to historical figures in Spanish.
Leí un libro sobre el rey Guillermo de Inglaterra.
I read a book about King William of England.
In a less common usage, 'guillermo' can appear in figurative or metaphorical speech, though this requires context as it is not standard.