title: Intercalation
text: # Intercalation
  
  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
  