noun
or avogadro constant | ̷ ̷ ̷ ̷| ̷ ̷(ˌ)drō-
Usage: usually capitalized A
Etymology: after Count Avogadro
: the number of atoms in a gram atom or of molecules in a gram molecule of any substance (as for oxygen the number of atoms in 16 grams), its value being 6.023 × 10 23 — compare avogadro's law