Active - is the most common, 'normal' state.
Lapsed members can not login to view members-only content but can login and renew via their profile.
Pending New/Upgrade/Renewal means that the application has been submitted but payment process was not fully completed (either payments is by check or online payment was started but did not finish) . It is up to the administrator to change status to active once the payment is received.
Also, each record can be archived - archived records do not count into billing plan limit.
Dmitry Buterin, Chief Apricot