bottleneck

pullonkaula

hankaloittaa

kaventua The narrow portion that forms the pouring spout of a bottle; the neck of a bottle.
In traffic, any narrowing of the road, especially resulting in a delay.
Any delay; part of a process that is too slow or cumbersome.

It is easy to create entries; processing the paperwork is the bottleneck.

The bottleneck in this computer program is the inefficient sorting process; we should replace it with a faster one.

The merge bottlenecked the traffic every morning.

The traffic bottlenecked at the merge every morning.