The term has several meanings. Scandinavian countries consider themselves socialist for their high levels of government support of education and healthcare, but so did the Soviet Union and similar countries with a state-run centralized command economy. When people in the US rally against "socialism" they are either thinking that what people in favor of socialism want is a centralized command economy or think that it is a slippery slope and that government support of health care will eventually lead to a Bolshevik insurrection or something.