serration n 1: the condition of being serrated; "the serrations of a city skyline" 2: a row of notches; "the pliers had serrations to improve the grip" 3: a single notch in a row of notches; "one of the serrations was broken off"
Serration \Ser*ra"tion\, n. 1. Condition of being serrate; formation in the shape of a saw. [1913 Webster] 2. One of the teeth in a serrate or serrulate margin. [1913 Webster]