On paper, the terminology of communism and socialism is drastically similar. Both calls for a "community-led, community-oriented" type of economy, in which each person creates based on what the community needs, rather than working based on one's own wants and needs. However, they differentiate based on the application throughout history, as well as how factual the application is to the defining term.
When one thinks of a communist country, the first few countries that come to mind is the USSR, North Korea, Vietnam (previously known as North Vietnam), Venezuela, etc., to name a few. The defining characteristics of each of these "pure communist countries" is that they are, in reality, a totalitarian state in which oppression is key, and that party popularity and support is critical in the functioning of the state... until it is not. The first example that we look at is the creation of Bolshevik party, led by Lenin, Alexander, and later Stalin. An underlying theme shared by them and the opposite political spectrum of the National Socialist German Worker's Party (NAZI), is simply the way in which they went about the changes. On one end of the spectrum, the workers are given the illusion in which they rule, while the mastermind that hold the power typically are in effect. On the other hand, while it may not seem that the worker's are given power, they actually are given power through the ideals imposed to them, a rather superflous power. In the communist regime, the ideals of the workers are simply taken up and championed by the leaders, only to be left in the dust when unneeded. This is rather exemplified in the results in which they bring, removing all workers who fail in falling under the party, and eliminating solely based on ethnicity and groups. Communism in part is what is used as the driving force in which to persuade the average worker to be given a taste of what their lifestyle can be, and then swiftly removing it and in return, giving the true, underworld picturesque. The failure of communism is potentially seen throughout history, with harrowing famines, inflated prices, as well as limitations on the products for the common people. Rather then being for the people, and, like a puppet with strings, by the people, it rather becomes a absolutism that forces others into decay.
Socialism, on the other hand, is simply Communism, without the overreaching goal of potentially eliminating the people with the hope of holding the powers of the land. In fact, it can be argued that socialism is technically the stepping stone towards communism, a much needed step towards "total" equality. After all, it may be argued that Socialism tries to combine the best of two worlds, using the framework of Capitalism and Democracy, and filling in the positivity's of Communist outlook within. In a socialist outlook, rather than having the state or government control the whole process, it is rather given to the community or organization (which can in turn be called "true communism"). However, this is a truly double edged sword, as the line is thin between staying as a socialist country and becoming a communist country. The power balance of the government and the people can be changed miniscually, with no effects in which the population can fight back. Many Nordic countries follow something called "democratic-socialism", which continues to give a larger portion of the power to the people. As such, the people "workers" continue to enjoy the "true sense of communism", and also bring about the usage of democracy as a whole. Revolution, which plays an important role in communism, is rarely used to make change, as in socialism there are already process that are eerily similar to those of a democratic process that allows room for change.
In the end, communism and socialism typically only rely on alliances with the United States. The US, with it's foundation built on Democratic process (while technically is known as a Republic), is known to fight against the effects of Communism when it arrives. Essentially, in needing to collude Democracy and Communism together, socialism is born, and, for good measure, Democratic-Socialist views that it leans more towards Democracy, rather than Communism.
To put simply, how are they different?
Socialism is only the first step into communism, and continues to allow for justification of usage of individualistic freedom, while Communism disregards all usages of Democracy.
