A mom who may sorta look like a mom, but not really. Make sense?
I have a friend that is often referred to as this (I don't think she realizes). She is cute but not gorgeous - there are so few "naturally" gorgeous after a "certain" age, I suppose.
She has a good body - nice shape, not too skinny or gym obsessed, but cute. She is casual, doesn't have to dress up or try too hard. Cute face, a small amount of makeup, hair usually up, not a conventional beauty; and definitely not the straw colored blonde or "follow me" trendy trying-too-hard clothes that are the norm here. (I am guilty of that).
She's different, not drop dead gorgeous and not ugly. I think that, and the way she treats others, and enjoys life, makes her beautiful. She is a great mom and likes to have a good laugh. Hell, I'd sleep with her