the.com/ref

means A short form of 'referee' — the official who enforces the rules and makes the calls in a sports match.

from A clipping of 'referee,' which comes from the verb 'refer' — rooted in Latin referre, 'to carry back' or 'relate.' The idea was someone to whom a dispute is referred for judgment, used that way in English since around the 1600s for arbitrators generally. The sporting sense of 'referee,' and then the clipped 'ref,' emerged in the 1800s as organized games needed an on-field judge — the short form arriving with the shouting that inevitably followed.