(x) Subsidiary. A subsidiary of a specified person is an affiliate controlled by such person directly, or indirectly through one or more intermediaries.
17 CFR § 210.1-02
Unless the context otherwise requires, terms defined in the general rules and regulations or in the instructions to the applicable form, when used in Regulation S-X (this part 210), shall have the respective meanings given in such instructions or rules. In addition, the following terms shall have the meanings indicated in this section unless the context otherwise requires.