cotrustee
noun
co·trust·ee (ˌ)kō-trə-ˈstē 
variants or co-trustee
plural cotrustees or co-trustees
: a joint trustee
As cotrustee, the beneficiary has the right to forbid the bank from making disbursements on the account without her approval.
Brigid McMenamin
Brigid McMenamin
Word History
First Known Use
1818, in the meaning defined above
Legal Definition
cotrustee
noun
co·trust·ee
ˌkō-ˌtrəs-ˈtē
: a joint trustee