a purpose; a goal; an objective

rational, reasonable, logical

An entry. / Filling in, filling out (such as forms or papers).

Frankfurt, Frankfurt-am-Main (the largest city in Hesse, in central Germany) / Frankfurt, Frankfurt-an-der-Oder (a sizable town in Brandenburg, in eastern Germany)

frankfurter, a kind of sausage

Hamburg (the second-largest city in Germany) / Hamburg (a state of Germany containing the city of the same name)

distance / mental distance, psychological gap

bacteriologist

archaeologist

One should be able to derive new understanding while revising what he has learned. Learning from the past.