to mediate (the usual word)

think deeply about

to think about (a person, thing)

turn over in one's mind

to look at at, think about, (oneself, ideas etc)

think about seriously; plan

to (fix one's attention on something and) think seriously and deeply (about it)

contemplate

to think deeply or dreamily, ignoring what is happening around one

think about, dream

to think (about something)

think about seriously

to thing seriously; (of some animals) to swallow food then return it to the mouth later and chew it

think about seriously