regular customer; general audience; general public
Refers to ordinary customers or the general public, as opposed to special guests, members, or invited attendees. The exact nuance depends on context: in a shop it means a regular (non-VIP) customer; at an event it means the general audience.
This event is open to the general public as well.
During members-only hours, regular customers cannot use the facilities.
Compound of 一般 (ippan, 'general') and 客 (kyaku, 'customer' or 'guest'). The word is a straightforward combination of these two common elements.