What is defined as a legal relationship involving a person and another who acts for the person?

The term that describes the legal relationship involving a person and another who acts on their behalf is "Agency." In an agency relationship, one party, known as the principal, grants authority to another party, known as the agent, to act on their behalf in business transactions or legal matters. This relationship is characterized by the trust and confidence the principal has in the agent to carry out the agreed-upon tasks.

In real estate, for instance, a real estate agent represents the interests of their client (the principal) in property transactions, negotiating terms and making decisions that align with the client's goals. This relationship is fundamental to many professional services and is governed by specific legal principles designed to protect both parties involved.

The other terms mentioned do not accurately describe the same relationship. A partnership involves two or more individuals who operate a business together and share profits and losses. A corporation is a legal entity that is separate from its owners and is created to conduct business. A trust is a fiduciary arrangement allowing a third party to hold assets on behalf of beneficiaries. Each of these concepts represents distinct legal relationships and structures, differentiating them clearly from the definition of agency.