Democracy and socialism
A major difference between democracy and socialism is the free market principle which allows buyers and sellers to agree on price without government interference. Democracy, a political system which promotes individual initiative, generally supports free markets. Socialism in most of its forms interferes with individual initiative.
Democracy and socialism are both political systems, although much of socialism is more concerned with the economy. Marxist countries have created socialism which transcends mere economics by combining a political despotism which enforces atheism.