What are spiracles? what are spiracles? openings into the tracheae of insects openings to the parabronchi openings into the alveoli of the lungs openings to the bronchi openings between the gills of a frog tadpole?

I believe the answer is openings into the tracheae of insects

Spiracle is an opening that connect to the respiratory organ. When opened, the spiracle will allow air from atmosphere to flow to the trachea. It could be found in insect like spider or in vertebrae like jawless fish. You could say that spiracle is similar to nostril in human