ns

n. one-billionth of a second

NS as an abbreviation can mean: In geography:Negeri Sembilan, one of the 14 states in Malaysia.Novi Sad, a city in SerbiaNova Scotia, as the official Canadian postal abbreviation for the provinceIn government and politics:Nasjonal Samling, a 1930s Norwegian national socialist political partyNational service, a name for the conscription system of some militariesNazism, also known as "National Socialism" in Germany, the ideology held by the National Socialist German Workers PartyNew Serbia (Нова Србија or Nova Srbija), a moderate nationalist political party in SerbiaNew Slovenia (also known as Nova Slovenija - Krscanski Ljudska Stranka), a right-of-centre political party in SloveniaPeople's Party, a political party in the Republic of Montenegro
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p.s., postscript, extra text added to a document; addition to a letter that was already finished; appendix to a book

ns, nano second, one-billionth of a second

Netherlands Rail, Dutch national rail company