A Lead

1. (countable) The act of leading or conducting; guidance; direction, course
2. (countable) Precedence; advance position; also, the measure of precedence; the state of being ahead in a race; the highest score in a game in an incomplete game.
3. (Britain, countable) An insulated metallic wire for electrical devices and equipment.
4. (baseball) The situation where a runner steps away from a base while waiting for the pitch to be thrown.
5. (uncountable, card games, dominoes) The act or right of playing first in a game or round; the card suit, or piece, so played
6. (acting) The main role in a play or film; the lead role.
7. (acting) The actor who plays the main role; lead actor.
8. (countable) A channel of open water in an ice field.
9. (countable, mining) A lode.
10. (nautical) The course of a rope from end to end.
11. A rope, leather strap, or similar device with which to lead an animal; a leash
12. In a steam engine, the width of port opening which is uncovered by the valve, for the admission or release of steam, at the instant when the piston is at end of its stroke.
13. (civil engineering) The distance of haul, as from a cutting to an embankment.
14. (horology) The action of a tooth, such as a tooth of a wheel, in impelling another tooth or a pallet.
15. Hypothesis that has not been pursued
16. The investigation stalled when all leads turned out to be dead ends.
17. Information obtained by a detective or police officer that allows him or her to discover further details about a crime or incident.
18. The police have a couple of leads they will follow to solve the case.
19. (marketing) Potential opportunity for a sale or transaction, a potential customer.
20. Information obtained by a news reporter about an issue or subject that allows him or her to discover more details.
21. (curling) The player who throws the first two rocks for a team.
22. (newspapers) A teaser; a lead-in; the start of a newspaper column, telling who, what, when, where, why and how. (Sometimes spelled as lede for this usage to avoid ambiguity.)
23. An important news story that appears on the front page of a newspaper or at the beginning of a news broadcast
24. (engineering) The axial distance a screw thread travels in one revolution. It is equal to the pitch times the number of starts.
25. (music) In a barbershop quartet, the person who sings the melody, usually the second tenor
26. (music) The announcement by one voice part of a theme to be repeated by the other parts.
27. (music) A mark or a short passage in one voice part, as of a canon, serving as a cue for the entrance of others.
28. (engineering) The excess above a right angle in the angle between two consecutive cranks, as of a compound engine, on the same shaft.
29. (electrical) The angle between the line joining the brushes of a continuous-current dynamo and the diameter symmetrical between the poles.
30. (electrical) The advance of the current phase in an alternating circuit beyond that of the electromotive force producing it.

Note that these noun (attributive) uses are all derived from the verb, not the chemical element in #Etymology 1.