Short-term economic profits refer to the excess of total revenue over total costs in a limited timeframe, typically when a firm is able to sell its goods or services at a price higher than the average total cost. These profits are significant in the context of market structures, particularly in perfect competition, where firms enter and exit the market freely based on the presence of profits. In the short term, firms can experience economic profits, but these profits often attract new competitors, driving down prices and potentially eliminating profits in the long run.