Kreislaufs

Kreislaufs is the genitive singular form of the German noun Kreislauf, which means cycle or circuit. The term is used to denote a closed sequence of processes or movements that repeat over time, and it appears in many fields. In biology and medicine, Kreislauf typically refers to circulatory systems, for example Blutkreislauf (blood circulation) and Lungenkreislauf (pulmonary circulation). The phrase des Kreislaufs describes something pertaining to the cycle, as in die Regulation des Kreislaufs or Störung des Kreislaufs. The concept also extends to non-biological cycles, such as hydrologische Kreisläufe (water cycles) or Kohlenstoffkreislauf (carbon cycle) when used in full compounds.

Etymology: Kreislauf is formed from kreisen (to circle) and laufen (to run). The idea is a closed, repeating path.

In usage, Kreislaufs is not typically used as an independent noun; it occurs as the genitive form in phrases such as des Kreislaufs des Blutes or des Kreislaufs des Körpers, and as the stem in longer compounds like Wasserkreislauf or Blutkreislauf. The plural Kreisläufe is used when referring to multiple cycles.