A more thorough explanation:

Definition: Laesio enormis vel ultra dimidium is a legal term that refers to an excessive loss or abnormal loss of more than half. In Roman and civil law, it has two meanings:

1. The sale of a thing for which the buyer paid less than half its real value. In this case, the seller could rescind the sale, but the buyer could keep the item purchased by paying the full value. This doctrine was usually applied to land sales.
2. The injury sustained by one party to an onerous contract when the overreaching party receives twice the value of that party's money or property. For example, if a purchaser pays less than half the value of the property sold, or a seller receives more than double the property's value, laesio enormis may exist. If co-owner co-heirs partition or sell property, laesio enormis may exist when the purchaser pays less than one-fourth of the value rather than one-half.

In Louisiana, laesio enormis is also known as lesion beyond moiety.

Example: If John sells his house to Jane for $50,000, but the real value of the house is $100,000, then laesio enormis may exist. In this case, Jane paid less than half the real value of the house, and John could rescind the sale. However, if Jane wants to keep the house, she would have to pay the full value of $100,000.

Explanation: This example illustrates the first meaning of laesio enormis. John sold his house to Jane for less than half its real value, which is considered an excessive loss. Therefore, John could rescind the sale, but Jane could keep the house by paying the full value.