A metric unit of length equal to one ten billionth of a meter (or 0.0001 micron); used to specify wavelengths of electromagnetic radiation WordNet 3.0 & Open English WordNet

The angstrom or ångström is a metric unit of length equal to 10−10 m; that is, one ten-billionth of a metre, a hundred-millionth of a centimetre, 0.1 nanometre, or 100 picometres. Wikipedia

Unit of length equal to 0.1 nanometre, also spelled ångström. Wikipedia Disambiguation

Unit of length; equals 0.1 nanometre Wikidata

A internationally recognised unit of length that is equal to 0.1 nanometre (nm). OmegaWiki

A unit of length equal to 10−10 meters (that is, one ten-billionth of a meter), approximately the size of an atom, and denoted by the symbol Å, used especially to measure the wavelength of electromagnetic radiation or distances between atoms. Wiktionary

A very small unit of length, 10 m. Wiktionary (translation)