From the 15th century and earlier (and also today within the fields of statistics and metaphysics) individual meant "indivisible", typically describing any numerically singular thing, but sometimes meaning "a person". From the 17th century on, individual indicates separateness, as in individualism.
Although individuality and individualism are commonly considered to mature with age/time and experience/wealth, a sane adult human being is usually considered by the state as an "individual person" in law, even if the person denies individual culpability ("I followed instructions"). An individual person is accountable for their actions/decisions/instructions, subject to prosecution in both national and international law, from the time that they have reached age of majority, often though not always more or less coinciding with the granting of voting rights, tax and military duties/ individual right to bear arms (protected only under certain constitutions). In line with hierarchy, ultimate individual human reward for success and responsibility for failure is nonetheless found at the top of human society.
in American law:
The Merriam-Webster's Dictionary of Law states: A "natural person" is "A human being as distinguished from person (as a corporation) created by operation of law. A 1910 legal dictionary states: "Individual: As a noun, this term denotes a single person as distinguished from a group or class, and also, very commonly, a private or natural person as distinguished from a partnership, corporation, or association."