Path of a fly ball (3)
I believe the answer is:
arc
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">path of a fly ball</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for arc that I've seen before include "Curved path" , "Rainbow, e.g." , "Section of circumference" , "Curving trajectory" , "Part of a circular line" .)