Meaning and name origin
Guillemette \gu(i)-lle-mette\ as a girl's name is of Old German origin, and the meaning of Guillemette is "determined protector". Guillemette is a variant of Wilhelmina (Old German): the second element of the source phrase literally refers to a helmet.
Guillemette is not a popular first name for females but a very popular surname or last name for all people (#13050 out of 88799, Top 15%) (2000 U.S. Census).
Displayed below is a comparison of the popularity of the girl name Guillemette and its source form. The only popular variation form ranked in the Top 1000/100 is Wilhelmina. (2014 statistics).