di·am·e·ter 
/daɪˈæmətɚ/ noun
plural di·am·e·ters /daɪˈæmətɚ/ noun 1 [count] : a straight line from one side of something (such as a circle) to the other side that passes through the center point
▪ The dotted line indicates the diameter of the circle. — see picture at geometry 2 : the distance through the center of something from one side to the other [count] ▪ What is the diameter of the tree trunk? ▪ a pipe with a diameter of two inches = a pipe with a two-inch diameter [noncount] ▪ Dig a hole that's two feet deep and three feet in diameter. — compare radius
▪ The dotted line indicates the diameter of the circle. — see picture at geometry
