Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Communication Breakdown; Confusion; Situational Awareness
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Chart Or Publication; Environment - Non Weather Related; Human Factors
FO (First Officer) and I both believed with confidence that ATC had instructed us to turn right to a heading upon reaching CLUSO. Neither of us had any doubt about the matter. When we turned at CLUSO; however; ORD TRACON advised us that we were supposed to turn at KAYTO instead. This came as a surprise to both of us. That was the first instance we had any doubt about what our clearance had been. At that point; second-guessing ourselves; the FO and I began to wonder whether we had read back 'KAYTO' or 'CLUSO' when first given the heading clearance. Both waypoints sound similar when pronounced; and this similarity may have contributed to this new doubt. So; we were not sure if the error was ours or ATC's. In any case; ATC informed us that there was 'no problem' with the turn and then gave us further vectors. There was no traffic conflict.In retrospect; the only thing that may have played a role in any confusion that may have occurred with either ATC or with us is that 'KAYTO' and 'CLUSO' can sound similar; causing the wrong term to be ensconced in memory.Consider not having waypoints in close proximity to each other that may sound similar when pronounced.
Air carrier Captain reported a track deviation during arrival to ORD after turning left at CLUSO Intersection rather than KAYTO Intersection as cleared. Captain stated CLUSO and KAYTO can be similarly pronounced and therefore confused by crews.