conductor

noun7

1. •
   One who conducts or leads; a guide; a director.

   • […]Zeal, the blind conductor of the will — 1687
2. •
   A person who conducts an orchestra, choir or other music ensemble; a professional whose occupation is conducting.
3. •
   A leader.
4. •
   Something that can transmit electricity, heat, light, or sound.

   • Falling conductors may come in contact with grounded objects or puddles of water. — 1952
5. •
   A person who takes tickets on public transportation and also helps passengers.

   • "[…] And one of the things that makes me feel safe is when I see the conductor." — 2022
6. •
   An ideal of a ring that measures how far it is from being integrally closed

   • If c is the conductor ideal for R in R then prime ideals not containing c correspond to localizations yielding discrete valuation rings. — 1988
7. •
   A grooved sound or staff used for directing instruments, such as lithontriptic forceps; a director.