Yes, in chemistry a pure substance means either an element or a compound. Thus, hydrogen, oxygen, sodium, iron, copper etc. are pure substances; and so are compounds such as water, sugar, ammonia, sodium chloride, methane, ethanol etc. A compound is composed of two or more elements combined in a fixed ratio by mass. Like an element, a compound also has a distinct chemical identity. A mixture is not a pure substance as it is a collection of two or more elements/compounds in varying ratio. Air, sea water, gasoline, vegetable oils, steel etc. are mixtures.
Hudson (CDP), Massachusetts. Hudson is a census-designated place (CDP) in the town of Hudson in Middlesex County, Massachusetts, United States. The population was 14,907 at the 2010 census.
Hudson is a city in St. Croix County, Wisconsin, United States. As of the 2010 United States Census, its population was  18,937, making it the principal and largest city of the Minneapolis - St. Paul metropolitan area (Wisconsin suburbs). The Hudson area however had a population of 39,713. The village of North Hudson is located directly to the north of Hudson. Hudson was settled in the summer of 1840 by Louis Massey and his brother in-law, Peter Bouchea. William Steets arrived at about the same time.