- The number of elementary entities in a mole. This numeric value is approximately 6.022142 × 1023. For instance, a mole of carbon-12 has approximately 6.022142 × 1023 atoms, and has a mass of 12 grams. Also known as Avogadro's constant. Its symbol is NA, or L.
- synonymAvogadro's constant
- Abbreviation of numerical aperture 2. Same as N/A.
Information & Library Science
- abbreviation in Internet addresses, the top-level domain for Namibia