bottleneck

bottleneck
noun

the neck or mouth of a bottle
瓶颈
a point of congestion or blockage, in particular
拥挤处，尤指
■a narrow section of road or a junction that impedes traffic flow
瓶颈路段
■a situation that causes delay in a process or system
（影响整个过程或系统的）障碍
a device shaped like the neck of a bottle that is worn on a guitarist's finger and used to produce sliding effects on the strings
（吉他手戴的）瓶颈形压弦器
■(亦作 bottleneck guitar)[mass noun]the style of playing that uses such a device
瓶颈压弦滑奏法