centerline

1. (engineering, trades) A line, either demarcated or imagined, representing the precise center (middle) of something (such that what lies on one side of it is precisely equal in size to what lies on the other side); the central axis represented by this line.Synonyms: ℄

2. (martial arts, boxing) An imaginary line connecting the center of two fighters' bodies while they face each other.Examples: "You might already know that, I don't know, but since you are training at home I didn't want you to be weaving wildly on each side of the rope - the goal is to pop up as tight as possible to the center line."; "take his lead leg out from under him. Just dont it when he is going for a power jab, just make sure your heads out of the center line"