"lead work; lead covering or frame of lead," mid-15c., verbal noun from lead (n.1). Printing sense is from 1855.
leading (n.2)
mid-13c., "a bringing by force," verbal noun from lead (v.1). Meaning "direction, guidance" is from late 14c.
leading (adj.)
1590s, "that goes first," present-participle adjective from lead (v.1). Meaning "directing, guiding" is from 1620s. Of persons, "having first or most prominent place," 1670s. In reference to theatrical companies, leading lady is from 1846; leading man from 1847.
the leading team in the pennant race
the country's leading poet
the leading man
we rode in the leading car
the leading edge of technology
leaden
leader
leaderless
leadership
lead-in
leading
lead-off
lead-up
leaf
leafless
leaflet