A stem friend is a term used in the LGBTQ+ community to describe a person who identifies as a stem lesbian. Stem is a combination of the terms "stud" and "femme," and refers to a person who is somewhere in between these two categories, bringing the perfect mix of masculine and feminine. Stem girls generally enjoy masculine hobbies and activities but have expressive feminine sexuality. They tend to look like a star when leaving the house, are often well-groomed, enjoy sports, and wear comfortable yet sexy clothing. Stem friends are typically women who love women and use she/her pronouns in communication.

It is important to note that the term stem is exclusive to the Black and Latinx LGBTQ+ community, and it is wrong for the Caucasian community to use the word stem in their daily life. The more appropriate label for white people whose expression and gender identity may be similar to a stem is soft butch or futch, which is a combination of butch and femme.

In general, a stem friend is simply a friend who identifies as a stem lesbian. Stem friends can be mentors in STEM fields, as in the "A Friend in STEM" mentorship program at the University of Minnesota. However, the term "stem friend" is most commonly used to refer to a friend who identifies as a stem lesbian and is part of the LGBTQ+ community.