In mythology, a chimera is a monster composed of distinct parts from several animals. The word "chimera" also has several meanings in biology, based on the mythical concept.
From Dungeons and Drawings, which, as you can see, is pretty great.
Biological chimeras include whole organisms consisting of at least two genetically distinct cells (you might be one), or proteins that consist of two or more proteins (or bits of proteins) fused together. Combining bits of protein is fairly common in synthetic biology. Last year's iGEM team fused whole fluorescent proteins with bits of other proteins responsible for transporting those other proteins to various parts of the cell. The chimeric protein glowed like a fluorescent protein, but, since it included another protein's "I want to be in the nucleus" tag, would be transported to the nucleus.