Nb

symbol

the chemical element niobium.

abbreviation, symbol

no-ball.

1. New Brunswick (in official postal use).
2. nota bene; take special note.

noun, symbol

the chemical element of atomic number 41, a silver-grey metal of the transition series, used in superconducting alloys.

mid 19th century: modern Latin, from Niobe, by association with her father Tantalus (so named because the element was first found in tantalite).