What is sciatica? Sciatica is pain, tingling, or numbness produced by an irritation of the nerve roots that lead to the sciatic nerve. The sciatic nerve is formed by the nerve roots coming out of the spinal cord into the lower back. It goes down through the buttock, then its branches extend down the back of the leg to the ankle and foot.
Definition of navigable - (of a waterway or sea) able to be sailed on by ships or boats, (of a website) easy to move around in Definition of navigable - (of a waterway or sea) able to be sailed on by ships or boats, (of a website) easy to move around in
Definition of channel for Students. 1  1 : the bed of a stream. 2  2 : the deeper part of a waterway (as a river or harbor) 3  3 : a strait or a narrow sea the English Channel.  4 : a passage (as a tube) through which something flows an irrigation 1  channel. 5 : a long groove.