bottleneck

Noun

• the narrow part of a bottle near the top

• a narrowing that reduces the flow through a channel

Verb

• become narrow, like a bottleneck
  • Right by the bridge, the road bottlenecks
    

• slow down or impede by creating an obstruction
  • His laziness has bottlenecked our efforts to reform the system
    

Related words

• Synonyms: 
  constriction , chokepoint