is a specific kind of: cerebrate, cogitate, think.

is a broader term that covers: premeditate | theologise, theologize | introspect | bethink | cogitate | question, wonder | puzzle | consider, study.

derivation: contemplation, musing, reflection, reflexion, rumination, thoughtfulness | meditation, speculation | muse | muller, muser, ponderer, ruminator | inquisitive, questioning, speculative, wondering | reflective | brooding, broody, contemplative, meditative, musing, pensive, pondering, reflective, ruminative | excogitative.