TESC Schedule code - what does it mean??

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I look at my schedule on my TESC OSS and there is a section with "Pass Aud" at the top
Does anyone know what it stands for??

Sorry if I sound really stupid here, but one of my classes doesn't anything in that "Pass Aud" section, whereas other classes do .... it's concerning me :willynilly:
Didn't want to ask TESC in case I'm supposed to know, and they raise an eyebrow and question my ability