Subsidiary
A company controlled by another company.
A subsidiary is a company that another company controls, normally by owning a majority of its voting shares. A wholly owned subsidiary is one where the parent holds every share.
Listed companies must publish a list of their significant subsidiaries as an exhibit to their annual report: Exhibit 21 for a Form 10-K, Exhibit 8.1 for a Form 20-F. Those exhibits are the single most useful public document for tracing what a company owns, because they are signed off as part of an audited filing rather than written by a marketing department.