Since a lot of women have started to call their female friends “girlfriends
That was the original meaning of the word before it ever had romantic connotations.
From Wikipedia…
According to the Oxford English Dictionary, the earliest meaning of the word “girlfriend”, from 1859 on, was to designate “a female friend; esp. a woman’s close female friend”. In the late 1800s, it took on the meaning of “A female with whom a person has a romantic or sexual relationship”.