A soft grey ductile metallic element used in alloys; occurs in niobite; formerly called columbium.

synonyms: atomic number 41, niobium.

Dutch: niobium
Polish: niob, Nb

A Latin phrase (or its abbreviation) used to indicate that special attention should be paid to something:
— The margins of his book were generously supplied with pencilled NBs.

synonyms: N.B., nota bene.