the Berasit Hebrew Dictionary

שנער

Often pronounced “Shinar”, 'seneyer' is generally thought to refer to the land of Sumer. It first appears in Genesis 10:10.

There is evidence that semeron might also apply to the same region.

Etymologically, 'seneyer' appears to be formed from the root words sen + neyer so its literal meaning is “tooth of a child” or “baby teeth”. Thus, it might refer to a previous civilization which the yeberi considered to be an early stage of their own culture, possibly the qedem.