Server reconciliation
Also said as Rubber-banding (when it goes wrong), Correction, Replay
When a server update arrives, take its word for that moment in the past, then re-apply every input it has not yet seen. If you predicted correctly, nothing on screen moves.
Updates are always old. Believing them outright drags you back a trip's worth of movement, twenty times a second. That is rubber-banding, and it makes prediction useless.
Say it
“Number every input. Each server update says the last number it processed, so drop those and replay the rest. If the replayed position is under 5 px off, blend over 100 ms; otherwise snap.”
Where you’ve seen it
In Valorant, clients predict their own movement and the server sends corrections when they diverge. Gabriel Gambetta's series Fast-Paced Multiplayer is the usual explanation of the method.
Not to be confused with client-side prediction
Prediction moves you now. Reconciliation is how that guess gets checked against the server without you noticing.