Admin
An admin is a member with elevated permissions. Admins approve pending bookings, finalise bookings, approve submitted expenses, edit asset and billing settings, invite and manage members, and confirm or dismiss reported squawks.
Admins also hold the syndicate-level powers: managing the paid subscription and closing the syndicate. There is no role above admin; ownership is expressed through shares, not through a role. A syndicate can have any number of admins, and must always keep at least one.
Treasurer is not a separate role; it is an admin who takes on the financial workflows (finalising bookings, approving expenses, recording payments). Use “treasurer” in prose when that is what you mean.