This is the 5611th most frequent Spanish word.
procesión
A religious or ceremonial procession.
Here, 'procesión' refers to a ceremonial parade or movement of people, often for religious purposes.
La procesión avanzaba lentamente por las calles del pueblo.
The procession was advancing slowly through the town's streets.
In this context, 'procesión' metaphorically describes an orderly group of moving subjects, in this case, ants.
Asistimos a la procesión de las hormigas cargando hojas.
We attended the procession of ants carrying leaves.
Here, 'procesión' is used abstractly to describe a sequence or continuation of events.