When talking about an influential woman in our lives, we often say: "She's like a mom to me."

She can be anyone: a favorite teacher, a cool aunt, a family friend. She can work in the cubicle next to you, live down the street or be a member of your cooking club.

Women who take on the role of second mom welcome us into their homes like we're part of the family. We can talk to them about anything. Sometimes it's even easier than talking to our own moms because, let's face it, even the closest, most satisfying relationship with a biological mother can be fraught with tension.

"Second moms exist because of a number of different circumstances," said Carol Bruess, a professor at the University of St. Thomas who specializes in interpersonal communication, "yet they all tend to function similarly: to fulfill a relational need."

Bruess said women seek out these relationships when their mother isn't around or there's not a close bond. Sometimes women — and men — find an additional mom simply because they enjoy the relationship with a close, supportive, often older woman in their lives.

While lots of us have these special relationships, how often do we take the time to honor them?

"I don't know that Hallmark makes a card for pseudo moms," said Marti Erickson, a developmental psychologist, and co-host and owner of the Mom Enough website and podcast. "Sometimes they're not even mothers themselves, but it's nice to appreciate mothering … whatever form it comes in."

On this Mother's Day, we'd like to introduce you to three women who are mothers to almost everyone they meet.