Added 9 October 2026 nanometer /ˈnænəˌmitɚ/ noun Categories: Describing WordsRare Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about nanometer at Wordnik → Where our words come from → A metric unit of length equal to one billionth of a meter. Related Words: micromillimetermicromillimetrenanometremillimicronnanonanotechnologynanometresnanometricmicrometresubnanometernanoscalenanoscopic Back to today's word