Narrative:

Working arrival coordinator; listened in on a conversation between a C90 controller and bearz sector regarding turbulence on the watsn STAR. The C90 controller used terms like 'more than moderate turbulence' and 'severe chop' on the line. There was also a recent [pilot report; PIREP] for 'one jolt of severe turbulence' just to the east. Multiple aircraft had reported these bad rides between 110-120 on the watsn STAR.I called up the C90 tmc shortly after and asked about the ride reports; concerned that we should come off the watsn STAR due to the turbulence. Was told no; they would slow to 250 and get more ride reports before changing arrivals.then; I asked about the terms being used and made note that there's no such thing as severe chop. Tmc told me that they were just relaying what the pilots told them; and that the pilots don't like to use the term 'severe turbulence' because it means they would need to ground the plane.this kind of terminology muddying is dangerous. It both weakens the actual meaning of severe turbulence; and leaves in question the situation at hand. It could easily cause more aircraft to experience unsafe and possibly damaging turbulence. It is simply not clear communication; even if controllers are just relaying what pilots said verbatim.outreach to airlines and all aviation groups about the meaning and safety issues behind turbulence reports. Encourage pilots to translate what they feel in to official terminology only. If something isn't actually severe; don't say severe. If it is severe; then say so and place safety above all else; particularly when it might affect a long string of aircraft following.controllers should work to clarify with the pilot the precise terminology needed to define the turbulence with official terms for pireps. Just repeating conflated terms doesn't help the problem.

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Original NASA ASRS Text

Title: Chicago Center Controller reported confusing terminology being used related to turbulence severity.

Narrative: Working Arrival Coordinator; listened in on a conversation between a C90 controller and BEARZ sector regarding turbulence on the WATSN STAR. The C90 controller used terms like 'More than moderate turbulence' and 'Severe Chop' on the line. There was also a recent [pilot report; PIREP] for 'One jolt of severe turbulence' just to the east. Multiple aircraft had reported these bad rides between 110-120 on the WATSN STAR.I called up the C90 TMC shortly after and asked about the ride reports; concerned that we should come off the WATSN STAR due to the turbulence. Was told no; they would slow to 250 and get more ride reports before changing arrivals.Then; I asked about the terms being used and made note that there's no such thing as Severe Chop. TMC told me that they were just relaying what the pilots told them; and that the pilots don't like to use the term 'Severe turbulence' because it means they would need to ground the plane.This kind of terminology muddying is dangerous. It both weakens the actual meaning of severe turbulence; and leaves in question the situation at hand. It could easily cause more aircraft to experience unsafe and possibly damaging turbulence. It is simply not clear communication; even if controllers are just relaying what pilots said verbatim.Outreach to airlines and all aviation groups about the meaning and safety issues behind turbulence reports. Encourage pilots to translate what they feel in to official terminology only. If something isn't actually severe; don't say severe. If it is severe; then say so and place safety above all else; particularly when it might affect a long string of aircraft following.Controllers should work to clarify with the pilot the precise terminology needed to define the turbulence with official terms for PIREPs. Just repeating conflated terms doesn't help the problem.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.