御古[ofuru] used article (esp. clothes)
手古摺る[tekozuru] to have much trouble
土耳古[toruko] Turkey
下稽古[shitageiko] rehearsal
懐古[kaiko] recalling the old days

擬古[giko] imitation of classical styles
擬古文[gikobun] classical style
稽古[keiko] practice
遠古登点[wokototen] marks to aid in reading Chinese classics
古え[inishie] antiquity

と考えられる[tokangaerareru] one can think that ...
一考[ikkou] consideration
勘考[kankou] consider
考え[kangae] thinking
考えてみれば[kangaetemireba] if you think about it

考える[kangaeru] to consider
考え込む[kangaekomu] to ponder
考え事[kangaegoto] (deep) thinking
考え出す[kangaedasu] to think out
考え直して[kangaenaoshite] On second thoughts ...