Where is a non-repeating meeting located?

A list of all upcoming meetings that you've scheduled can be found on the Meetings page in the web portal: https://zoom.us/meeting
Those meetings are also listed in the desktop app under the Meetings tab. 

Hope that helps and please make sure to mark the solution as accepted if this information is what you needed.

I do thank you for the reply, but it is not listed there.  Every 'repeating' meeting is, but none of the non-repeating ones are.

Have you checked the Previous tab on that page? Sometimes users schedule a meeting for a specific date, use it then, then continue using it. Since its not officially recurring, only the first, scheduled date is tracked by Zoom and thus the event is technically in the past. 

I would also check to make sure you are signed-in to the same account between the web portal and wherever you are scheduling the meetings. Often when using a scheduling integration, such as Outlook plugin or the Chrome/Firefox extension, you are signed-in to one account in the scheduler and then a separate account on the web portal. An easy way to check is by comparing your PMI in the web portal (found on your Profile page) and the scheduler (try scheduling a meeting and see what is listed as your PMI).

I have, indeed, checked the previous tab, and, as you suggested, checked to make sure I've only one account.  Nothing.

Where/how did you schedule those non-repeating meetings? On the desktop client? The web portal? Through a scheduler extension/plugin? 

I use a desktop computer and go to this url to start a scheduled meeting:  https://zoom.us/meeting#/upcoming.   It looks like