~3 min read
Encyclopedic overview
12 sectionsContents
- Chemistry and physics
- Biology and medicine
- Places
- Current
- Historical
- Names and titles
- Art and entertainment
- Transport
- Language
- Organizations
- Other uses
- See also
NA, N.A., Na, nA or n/a may refer to:
==Chemistry and physics== Sodium, symbol Na, a chemical element Avogadro constant (NA) Nucleophilic addition, a type of reaction in organic chemistry Numerical aperture, a number that characterizes a range of angles in an optical system nA, the symbol for nanoampere Naturally aspirated engine
Excerpted from Wikipedia’s “Na” article, available under the CC BY-SA 4.0 licence.