A person who owns something is called owner. The thing owned is called their property. It can also be called possession, but "possession" is a wider term which can also refer to control or occupancy of something for which one does not necessarily have private property rights.
Ownership of people
Ownership is normally of things or animals. An exception is the case of slavery, where a person, called a "slave", is considered the "property" of another person, their "owner". Another case that nearly went as far, historically, was the relationship of lords and their serfs in feudalism, or the situation of women in a harem.
Exactly what constitutes ownership of a person and what doesn't is not easy to define by strict criteria. Typical characteristics of an ownership situation are:
- the owned person enjoys considerably less freedoms than other people
- the owned person is restrained in their unfreedom, physically, emotionally and/or by law
- the owner has the power and/or right to give orders, expect obedience and control what the owned person is doing
- the owner has the power and/or right to punish the owned person, possibly severely
- in certain cases: the owner has the power and/or right to use the owned person sexually
Some of these characteristics are (or were historically) also found to certain degrees:
- in captivity
- in (judicial) imprisonment, reformatory institutions, boot camps, etc.
- in religious orders (monks, nuns, novices)
- in certain professions (soldiers, sailors, domestic servants, prostitutes, etc.)
- in families: husband/wife, parent/child
These are however normally never considered cases of "ownership", although in extreme cases in practice they could nearly go as far.
Today, ownership of people is considered a severe violation of human rights and is generally illegal. However the usual forms of judicial punishment, including incarceration for extended periods or for life, are not generally seen as human rights violations, even when the unfreedom of a prisoner can equal or resemble that of a slave.
Ownership/property in BDSM
In BDSM, the exclusive power and control of an ownership relation has positive connotations and an erotic appeal to many people. Consensual ownership is usually found in "classic" BDSM master/slave relationships: the slave or submissive becomes the "property" or "possession" of their master or mistress, who is then their "owner". It is not ownership in any legal sense, and due to its consensuality it is not illegal in most countries, nor is it considered a violation of human rights. Sometimes such an ownership is codified in a slave contract, and sometimes its official beginning is celebrated in the ritual of collaring.
Being someone's "owner" in a BDSM relationship means, above all, to have exclusive rights, whereas a "master" or "mistress" may or may not be the person's only dominant (play) partner. Also, ownership relationships tend, or are thought, to be generally longer-term and 24/7.