What is a flow table? Openflow
As the links in the question suggest, flow-table is a broad term. A forwarding table uses IP address or MAC addresses to decide the next hop for the packet.  

But a flow table may use any of the information within the packet to decide the next hop for it e.g. incoming switch port, TCP port/IP address (src or dst), VLAN tag etc.


  A flow is defined as all the packets matching a flow-entry
  in a switch’s flow-table. Flow entries are quite general, and
  resemble ACL entries found in firewalls—although here they
  can include fields from layers 2, 3 and 4.
  
  (from Implementing an OpenFlow Switch on the NetFPGA
  platform by J. Naous et al)