How does Halacha define the concept of ownership in legal transactions?

The concept of ownership in Halacha is primarily defined through the presumption of rights known as Hazak. Hazak refers to a legal presumption that the person currently in possession of an item is the rightful owner unless proven otherwise. This presumption plays a crucial role in determining ownership, especially in disputes over possession and property rights.

While contracts can indicate ownership, they are not the sole means by which ownership is established in Halacha. Ownership can also arise from being in possession of something for a length of time, which is recognized under the principle of Hazak. This principle highlights that possession plays a vital role in establishing ownership in Jewish law.

Communal agreements and gifts or donations represent different aspects of legal transactions but do not encapsulate the broader and essential principle of ownership as defined by possession and the legal presumption of rights. Therefore, Hazak is foundational in understanding how ownership is determined within Halacha.