Seneh
Seneh is the name of one of the two rocky crags that flank the pass at Michmash, the terrain Jonathan had to cross in his solo approach to the Philistine garrison.
The Crag at Michmash
The text fixes both rocks by name: "And between the passes, by which Jonathan sought to go over to the Philistines' garrison, there was a rocky crag on the one side, and a rocky crag on the other side: and the name of the one was Bozez, and the name of the other Seneh" (1Sam 14:4).
Seneh is the southern marker of that pass — a feature of the geography rather than a settlement. Its mention sets the stage for Jonathan's climb: the two named crags identify the narrow place through which the attack on the garrison ran.