Medical Definition of Human immunodeficiency virus. Human immunodeficiency virus: HIV, the cause of AIDS. HIV has also previously been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus. No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme.
Definition of custody for English Language Learners. 1  law : the legal right to take care of a child (such as a child whose parents are divorced) : 2  the state of being kept in a prison or jail. : 3  the act of protecting or taking care of something.
In contrast to physical custody, legal custody refers to which parent makes major decisions about the child's welfare. Major decisions may refer to issues surrounding the child's education, health care, or religion. Like physical custody, legal custody may be awarded solely to one parent.