If you're asking what the definition of hymenotomy is, it literally means "to cut into the hymen."
Some hymens are delicate and will break (with a variable amount of pain) during sports or other strenuous physical activity, or when inserting a tampon. Some do not break until their owner's first experience of penetrative vaginal intercourse or sex toy usage.
However, some are too thick to break easily or at all, and some heal whenever stretched or torn. This problem can be addressed by the surgical procedure of hymenotomy. While a hymenotomy consists of making incisions in the hymen tissue to widen its aperture, a similar procedure called a hymenectomy is a complete removal of the hymen.
In effect, there is little difference between the two procedures--the recovery process is the same, with the exception of the fact that stitches (absorbable sutures) are required by a hymenectomy and not by a hymenotomy. Undergoers of either procedure tend to report improved comfort with inserting tampons or otherwise penetrating their vagina.