There are several "status" that a domain can assume during its activity. Here is a short list.
AddPeriod
It's the initial status of the registration. If the registrant erases the domain name in this period the Registrar can refund him/her the whole amount of the registration;
autoRenewPeriod
The domain auto-renews and the registrant doesn't have to carry on any action;
Inactive
The nameservers are not associated with the domain and the name resolution cannot be processed;
ClientHold
A domain is set to Client Hold status when it fails to pass the WhoIs verification procedure required by ICAAN. You will not be able to use your domain until you validate the data required from the authority.
Ok
The domain is active and all the operations can be regularly processed;
pendingCreate
A request for a domain registration is going to be processed;
pendingRenew
A domain renewal is going to be processed;
pendingDelete
The domain has been in redemptionPeriod for 30 days and will not be restored. It will be in this status for several days and then deleted;
pendingRestore
The domain has been in redemptionPeriod and the Registrar is restoring the domain after receiving all the required documents;
pendingTransfer
The domain is transfering or a transfer request is going to be processed;
redemptionPeriod
The registrant asked the Registrar to cancel the domain that is going to be in this status for 30 days. 5 days later the domain will be canceled and then available for registration again;
renewPeriod
The domain has been renewed by the Registrar.