Hi Tejas,
Is these terms related to WBS Budget ?
If yes, then they are just general terms FI use in WBS.
Actual : Actual budget assigned to WBS
Assigned : Budget consumed after SC is approved and PO is created
Committed : Budgete assigned to a SC or PR (PO not created)
Available : Available budget (Actual - Assigned - Committed)
Best Regards,
Anil