1. One employed to steer a vessel; a helmsman; a steersman.
2. Specifically, a person duly qualified, and licensed by authority, to conduct vessels into and out of a port, or in certain waters, for a fixed rate of fees.
3. Figuratively: A guide; a director of another through a difficult or unknown course.
4. An instrument for detecting the compass error.
5. The cowcatcher of a locomotive. Pilot balloon, a small balloon sent up in advance of a large one, to show the direction and force of the wind. Pilot bird.
(Science: medicine) same as blackfish.
Origin: F. Pilote, prob. From D. Peillood plummet, sounding lead; peilen, pegelen, to sound, measure (fr. D. & G. Peil, pegel, a sort of measure, water mark) – lood lead, akin to E. Lead. The pilot, then, is the lead man, i.e, he who throws the lead. See Pail, and Lead a metal.