1. The political philosophy that the means of production should be owned by the working public rather than individuals. This can be interpreted in a vast number of ways. For instance, the public may own property through the government or through various workers' organizations.
Socialism is not social democracy (socialism has nothing to do with taxing people or pouring money into welfare programs). Nor is socialism necessarily communism (many socialists believe in the right to personal property and not in the redistribution of income).
To put it briefly: socialism is the idea that those who work to create a profit should receive it. You can make money by working but not by exploiting others.
2. The extension of democratic ideals into the economy.
Neither Cuba nor Sweden lives up to the ideology of socialism.