"fireman's scaling ladder," short for pompier ladder (by 1893), French, literally "fireman," from pompe "pump" (see pump (n.1)).
Entries linking to pompier
pump n.1
"one of several kinds of apparatus for forcing liquid or air," early 15c., pumpe, which is probably from Middle Dutch pompe "water conduit, pipe," or Middle Low German pumpe "pump" (Modern German Pumpe), both from some North Sea sailors' word, possibly imitative of the sound of the plunger in the water.
Earliest English uses are in reference to a device to raise and expel bilge water from ships. Late Old French pompe probably is from Germanic. Pumps themselves are very ancient, which makes the late appearance of the Germanic word odd. From 1670s as "an act of pumping." Pump-action in reference to a type of repeating firearm is attested in advertisements for them from 1912.