Student or Learner
i have heard it from bleach episode 24
A spiracle is an air hole, such as a whale has in the top of its head. Other species possess this mechanism as well.
One reference explains that:
The spiracle of Ixodes ricinus (L.) (Ixodidae: Metastigmata: Acarina): a passive diffusion barrier for water vapour.
I hope this is helpful.