Jockey has two main meanings:

1. A professional athlete who rides horses in races. Jockeys are typically small and light (usually under 120 pounds) because horses run fastest when carrying less weight. They wear colorful silk uniforms called silks that represent the horse's owner. Being a jockey requires tremendous skill: they must control a 1,000-pound animal running at 40 miles per hour while making split-second decisions about when to speed up, hold back, or move to the inside lane. Famous jockeys like Willie Shoemaker have won thousands of races during their careers.
2. To maneuver for position or advantage, often in a competitive or crowded situation. At the starting line of a race, runners might jockey for position, trying to get the best spot. In a meeting, people might jockey to sit near the boss. Students might jockey to be first in the lunch line. The word suggests strategic positioning where everyone's trying to get ahead, like horses and their jockeys crowding together at the start of a race, each looking for the best path forward.