On a port configured as access port, it can only belong to one and one vlan only. On a trunk port configured as dot1q iith software release 8.3(1) and later releases, instead of reserved VLANs, we now have only user and internal VLANs. VLAN manager no longer permanently sets aside VLANs for features that require them; they are now dynamically assigned as needed. The entire VLAN range (1 to 4094) is now available for user (and internal) VLANs.
With ISL I believe it's 1005 vlans.