bottleneck
n.n. a place or stage in a process where everything slows down because there is not enough space or time. It is like the narrow neck of a bottle that stops liquid from pouring out quickly.
n. a point of congestion or blockage in a system that stops or slows the entire flow of progress. Often used in business or traffic contexts to describe a specific stage where capacity is limited.
The narrow bridge is a major bottleneck for morning traffic.
The legal department became a bottleneck because they only had one person available to sign off on all the new contracts.
Identifying the production bottleneck allowed the factory to increase its total output by twenty percent without hiring any additional staff.
From bottle + neck.
Often used metaphorically in business, computing, and logistics.