What is an anteverted uterus?

A normal one.
If you look at a diagram of a woman from the side her vagina goes from her vulva up and back to the cervix and then the uterus goes straigt up or falls slightly forward from the cervix. That is an anteverted uterus.
The opposite is a retroverted uterus where the uterus goes backwards from the cervix. about 20% of women have a retoverted uterus and it doesn't usually cause any problems.