Alternative form of lead-in

Used other than figuratively or idiomatically: see lead, in. / To introduce, to mark the beginning of something, especially in music.

(linear algebra) A main diagonal.

On a steam locomotive, an unpowered wheel located in front of the driving wheels.

On a steam locomotive, an axle connecting a coupled pair of unpowered wheels located in front of the driving wheels.

On a steam locomotive, a railroad truck to which wheel axles (and, hence, wheels) for one or more coupled pairs of unpowered wheels are attached through bearings, located in front of the driving wheels.

Of or pertaining to the leading edge of an airfoil / (by extension) leading, latest or most up-to-date

(aeronautics) The frontmost edge of a wing or other airfoil of an aircraft; sometimes contains slots or slats / (by extension) The foremost part of a trend etc; a vanguard

plural of leading light

(idiomatic) An acclaimed expert, one of the foremost experts, a luminary. / (nautical, navigation) A light that helps to guide vessels into a port.