Auxiliary has multiple meanings depending on the context. Here are some definitions from the search results:

• Auxiliary verb: Also called a helping verb, is a verb that is used with another verb (or two other verbs) in a verb phrase. The auxiliary verbs are used to form the perfect tenses and the progressive tenses. Another kind of auxiliary called a modal verb is used to change a verbs meaning to something other than simple fact (as to indicate permission, ability, prediction, possibility, or necessity).

• Supporting or assisting: Giving help or support, especially to a more important person or thing. For example, auxiliary equipment is extra equipment that is available for use when necessary.

• Subordinate or additional: Acting in a subsidiary or subordinate capacity, or being additional or supplementary.

• Navy vessel: A naval vessel designed for other than combat purposes, such as a tug, supply.

• Person or organization: A person or thing that gives aid of any kind, or an organization allied with, but subsidiary to, a main body of restricted membership, especially one composed of members relatives.

In summary, auxiliary can refer to a verb that helps form verb phrases, or to something that provides support or assistance. It can also refer to a navy vessel, a person or organization that gives aid, or something that is additional or supplementary.