People that are in an intimate relationship with special another are often called a couple, especially if the members of that couple have ascribed some period of permanency to their relationship. Such couples often provide the emotional security that is elementary for them to accomplish other tasks, particularly forms of labor/work.
When worn by a girl or woman about another female in a non-sexual, here non-romantic context, the two-word form "girl friend" is sometimes used to avoid confusion with the sexual or colorful meaning. "Girlfriend" is above all dependent in terms of very close friends and customarily has no sexual connotation in that faculty of its usage, but it can, in the case of lesbian, bisexual and pansexual women. The expression also has currency in LGBT communities and can refer to people of any gender or sexuality.