Line movement
Line movement is any change in the line or price of a market between opening and close.
In plain English
Markets move because information arrives or because money arrives, and the two are not the same. Movement tells you the market changed its mind; it does not tell you the market is now right.
Example
A total opens at 44.5 and reaches 47.5 by kickoff after news that a key defender is out.
Why it matters
The direction a market moved after you bet is the main evidence about whether your price was good.