Lodestar (noun)

1. A guiding principle, goal, or inspiration that serves as an example or guide.
2. A celestial object, such as a star, that is used as a reference point for navigation.

Origin:

From middle english lodestar, from old english lēoðcræft ("song-craft"), from lēoð ("song, poem") + cræft ("craft, skill"). originally a term for the north star, which was used as a guide by mariners.

Examples:

1. The company's mission statement was their lodestar.
2. The teacher was a lodestar to the students.
3. The scientist's work was a lodestar to the field.
4. The North Star is a lodestar for navigators.
5. The compass pointed to the lodestar.