A closed-form expression is a mathematical equation that can be evaluated using a finite number of operations. Some synonyms for a closed-form expression include explicit equation, analytical expression, exact solution, or algebraic formula. These terms all describe an equation that can be solved precisely, without the need for iterative calculations or approximations. In contrast, open-form expressions, also called iterative solutions, require repeated calculations to achieve an accurate result and are less precise. Closed-form equations are often preferred in math and science because they provide a clear and concise solution, making it easier to analyze and interpret the results.