Intercalation may refer to: Intercalation (chemistry), insertion of a molecule (or ion) into layered solids such as graphite Intercalation (timekeeping), insertion of a leap day, week or month into some calendar years to make the calendar follow the seasons Intercalation (university administration), period when a student is officially given time off from studying for an academic degree Intercalation (geology), a special form of interbedding, where two distinct depositional environments in close spatial proximity migrate back and forth across the border zone Intercalary chapter, a chapter in a novel that does not further the plot. See also frame story (sometimes called intercalation). In biology: Intercalary segment, an appendage-less segment in the segmental composition of the heads of insects and Myriapoda Intercalation (biochemistry), process discovered by Leonard Lerman by which certain drugs and mutagens insert themselves between base pairs of DNA Intercalated cells of the amygdala Intercalated cells of the collecting duct Intercalated disc of cardiac muscle Intercalated duct of exocrine glands