1. Relating to or being an organism, part, or molecule that is a chimera: chimeric mice; chimeric proteins.

2. Relating to a monoclonal antibody produced from the cells of a nonhuman organism, usually a mouse, in which a portion of the antibody has been replaced with a human sequence of amino acids. This is done in the laboratory by replacing part of the DNA sequence in the nonhuman cells with a sequence of human DNA.