(idiomatic) The amount of time between the initiation of some process and its completion, e.g. the time required to manufacture or procure a product; the time required before something can be provided or delivered.

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.

(less common) Synonym of first fiddle

(chemistry) A poorly-characterized oxide of lead, Pb₂O; it is a black, amorphous solid

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

The material (usually black or dark gray) which allows a pencil to work. Usually a mixture of graphite and smaller amounts of other material, but not actual lead.

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.

(music) A singer (or one of a small group of singers) who provides lead vocals to a song