1. something totally unrealistic or impractical: a wildly unrealistic idea or hope or a completely impractical plan
2. genetics organism with genetically different tissues: an organism, or part of one, with at least two genetically different tissues resulting from mutation, the grafting of plants, or the insertion of foreign cells into an embryo
3. embryology biotechnology organism with DNA from different sources: an organism that has genetic material from a variety of sources as a result of the insertion of unspecialized cells stem cells from other species into an embryo
