The term 'UNIT HEREDITARY' is a combination of two words, 'UNIT' and 'HEREDITARY'. UNIT refers to a single entity or element, while HEREDITARY refers to something that is passed down from one generation to the next. The crossword solution for this term is 'GENE', which is a UNIT of heredity that is passed down from parent to offspring. Genes are responsible for the physical characteristics and traits that are inherited from one generation to the next.