"lead work; lead covering or frame of lead," mid-15c., verbal noun from lead (n.1). Printing sense is from 1855.
mid-13c., "a bringing by force," verbal noun from lead (v.1). Meaning "direction, guidance" is from late 14c.
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.