Dhanishta comes from dhana, meaning wealth. The name means the wealthiest or the most abundant, and it is the only nakshatra named directly after prosperity.
In Hindu mythology, the eight Vasus are the gods of the elements: earth, water, fire, wind, sky, moon, sun and stars. They are the material substance the world is actually made of. Bhishma from the Mahabharata was one of them, born as a human under a curse. A star whose deities are the eight elements is a star about resources in the widest sense.
The symbol is a drum, and a drum keeps time. Separate players become a group only when somebody keeps the beat, and that coordination is what Dhanishta actually does.
Its shakti (the special power a nakshatra carries) is abundance and renown. Wealth here means having enough of whatever the situation needs, money included, and being known for being able to supply it.
Dhanishta is known for music, wealth and organisational ability. Natives tend to be the person who gets things running: the one who fixes the schedule, finds the money, or holds the rhythm while everyone else plays.