An affiliate is a separate company that is connected or partners with the main company somehow. A subsidiary is a separate company that is owned by, and takes orders from, the main company. A branch is a unit or outlet or store of a company.
Just to explain, I need to make the distinction between Subsidiary and afiliate cmpanies. My context is:
"Associated Companies" means any parent, subsidiary company or affiliate of Elitehill Trading Limited, which trades as XXX.
My translation so far is:
Les ‘Societes Associees’ veut dire toute societe mere, filliale ou affiliate de Elitehill Trading Limited, qui fait du commerce au nom de DUO.