Rumination (noun)

1. The act of thinking deeply about something; pondering.
2. The act of chewing the cud, as a ruminant animal does.

Origin:

From the latin word ruminatio, which means "chewing the cud" and is derived from the verb ruminare, meaning "to chew the cud".

Examples:

1. He spent hours in rumination trying to find a solution to the problem.
2. Her rumination on her mistakes helped her learn and improve.
3. The cow was engaged in rumination in the field.
4. His rumination on the events of the day led to a deeper understanding.
5. She needed some time for rumination before making her final decision.