The definition implies to individuals or concerns (i.e. companies) (See FAR 31.205-33 (d) (7)).
Under Contracts with USAID (all Contractors regardless of type):
FAR 44.101 define Subcontractor as “any supplier, distributor, vendor or firm that furnishes supplies or services to or for prime contractor or another subcontractor”.
This means Consultant Agreements are Subcontracts and require consent per 52.244-2.
Be able to say “Of course, here it is!” to the auditors and see their faces turn sad :-( a little for losing such a low hanging fruit in non-compliance findings….