Sentinel \Sen"ti*nel\, v. t. [imp. & p. p. {Sentineled}or {Sentinelled}; p. pr. & vb. n. {Sentineling} or {Sentinelling}.] 1. To watch over like a sentinel. ``To sentinel enchanted land.'' [R.] --Sir W. Scott. 2. To furnish with a sentinel; to place under the guard of a sentinel or sentinels.