Endometritis and endometriosis are two different disorders.
On the one hand, endometritis is the inflammation of the endometrium. Generally, endometritis is caused by an infection by microorganisms such as chlamydia or gonorrhea.
Endometriosis, on the other hand, is the presence of endometrial tissue outside the uterine cavity. Endometrial tissue is most commonly seen in the ovaries or fallopian tubes, although it can also be present in other locations.