Suitable or appropriate; keeping with expectations, norms, ideals, or rules.
"[Plant] rescues are usually organized by local garden clubs, but before you grab your shovel and head for the door, check with local government agencies to make sure you're in line with regulations." — "Garden Superheroes," Garden Gate, Jan/Feb 2006, Issue 67, p.45
(of three or more objects) Positioned in a straight line.
Please stand in line for the pledge of allegiance.
Assuming a position in the future.
He's in line to be the fastest runner of all time.
One behind another; in a queue
I'm waiting in line at the bakery.