Most commonly mispronounced words: serious /ˈsɪə.ri.əs/ # series /ˈsɪə.riːz/ 1. serious - severe in effect; bad 2. series - 1. a number of similar or related events or things, one following another 2. a number of games played by two teams Examples: 1. Why are you so serious ? 2. We need to undertake some serious measures to solve this problem. 3. Series of road accidents resulted in casualties. 4. The two baseball clubs played a five-game series .