atomic number 5

Từ điển WordNet v3.1 - WordNet Dictionary

noun

a trivalent metalloid element;
occurs both in a hard black crystal and in the form of a yellow or brown powder
• Syn:
boron, B
• Derivationally related forms:
boronic (for: boron), boric (for: boron)
• Hypernyms:
chemical element, element
• Substance Holonyms:
kernite, borax