Pyotr Ilyich Tchaikovsky (1840-1893) Most famous Russian classical music composer wrote in a variety of genres. He composed symphonies, operas, concertos, chamber music, sacred choral music, overtures, suites and ballets.
Medical Definition of Dizygotic twin. Dizygotic twin: A twins who have shared a common uterine environment with its twin but is due to a different fertilized ovum. Dizygotic twins are also called fraternal twins. Last Editorial Review: 6/9/2016.
A heterokaryon is a fungal cell which has two or more genetically-distinct but allelically-compatible nuclei, as suggested by this resource, as well as this Wikipedia article. A dikaryon is a fungal cell which has precisely two genetically-distinct but allelically-compatible nuclei, as shown here and here. In this sense, a heterokaryon is a general term, whereas a dikaryon is a specific term. A dikaryon and a trikaryon (although not often seen in literature) are both heterokaryons.