Concrete has cement as an ingredient, they are not the same thing.
Concrete is made of cement (a very fine powder made from limestone, sand, clay, and iron ore), water, sand and stone. Proportions of these ingredients are crushed and heated in a kiln to form “clinker”. The clinker is crushed again with gypsum and a number of other ingredients, and the result is a fine powder that we know as cement. The strength of concrete comes from the reaction between water and “hydration”, the chemical compounds in cement. Aggregates in concrete such as sand and stone, coarse and fine are for volume only and are not active ingredients in the hydration process.