nb has definitions from the fields of chemistry,writing
1
[ noun ] (writing) a Latin phrase (or its abbreviation) used to indicate that special attention should be paid to something

Synonyms

nota_bene n.b.

Examples

"the margins of his book were generously supplied with pencilled NBs"

Related terms

note

2
[ noun ] (chemistry) a soft gray ductile metallic element used in alloys; occurs in niobite; formerly called columbium
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