hi! you may be interested in some earlier posts, mostly featuring flaired user /u/vertexoflife
if you have follow-up questions on locked threads, ask them here & mention the relevant user's username so they'll be auto-notified
Do you mean by the US legal definition?
An oft repeated statement is that at no point in the US constitution or founding text like the Bill of Rights does it clearly define/grant the right of privacy.
However Louis Brandeis before he became a Supreme Court Judge laid the foundation in a Harvard Law Review article called "The Right to Privacy" in 1890.
later in one of the most important legal cases Griswold v. Connecticut enshrined the idea that yes indeed there is a right to privacy. To understand the impact of this case look no further then Roe v. Wade. The Griswold case was used as a lynch pin for its decision in support of abortion.
The justices in Griswold argued that though it is not explicitly stated that their is a right to Privacy, the first, fourth, and ninth amendment all address it obliquely.
They argued that those amendments create a penumbra or emanations of rights that where not stated, that being privacy. So in essence they "created" the right to privacy out of the what they assumed the intent of the writers of the first, fourth and ninth amendment where.
Now mind you their is still some that debate if this "Legal Fiction".
Arguments against it is like a real penumbra what happens when the sun (justices) changes positions. Do those rights disappear? Should judges make up new rights not explicitly written into the constitution? etc. etc.