An "inner ring" can refer to several things, depending on the context. Generally, it describes a component or area that is closest to the center or core of something else. 

Here are a few common meanings of "inner ring":

1. In bearings:

• Needle roller bearings:

  An inner ring is a hardened, precision-machined component that provides a raceway for the needle rollers, often used when the shaft itself cannot be hardened or machined for the bearing. 

• Ball bearings:

  The inner ring, also known as the inner race, is the rotating part of the bearing that is mounted on the shaft and carries the balls. 

• Other bearings:

  Inner rings can also be found in other bearing types, serving the same purpose of providing a raceway for the rolling elements. 

2. In geography/urban planning:

• Urban areas: An inner ring can refer to the area surrounding the center of a town or city, typically where people live.
• Suburbs: The inner ring of a city may also be referred to as inner-ring suburbs. 

3. In social circles/groups:

• Formal or informal groups:

  An inner ring can describe a small, exclusive group within a larger organization or community. 

• "The Inner Circle":

  This term often refers to a small group of advisors or influential people close to a leader or decision-maker.