look up any word, like spook:
 
1.
when a professor keeps pushing back the deadline to accommodate students who do not turn their work in on time, an indeterminate due date is a zombieline.
"I should just make my deadlines zombielines since they keep coming back to life when you students don't turn anything in."
by Oracular April 09, 2014
 
2.
When people subconsciously (or at times intentionally) form a significantly long line in an area next to much shorter lines for no apparent reason. Zombie lines are usually seen on the road (especially at intersections) involving drivers, but also apply to checkout lines in a store.

This action is similar to how zombies behave, one aimlessly following the other. Also see: lemming
I don't know why there are 20 cars in the middle lane when there are 5 cars in the left lane and 2 in the right lane. Definitely a zombie line.
by Shaun of the WTF November 26, 2010