Term
Line Call
Telling others, by voice or hand signal, that the ball was out.
Telling others, by voice or hand signal, that the ball did not land in the area it had to land in (that it was out) (Section 2, Definitions, 8.F). In matches without a referee, players make the calls for the lines on their own side of the court (8.A).
If the ball touches the line even a little, it is in (8.B, 8.E, A ball that touches the line is in).
See it in a figure
This figure is from the rule "A ball that touches the line is in".
How to read the sources: numbers like (8.F.4) are rulebook sections, and links are outside sources. An "Author's note" is the author's personal experience, not an official rule.