symbiotic--Dad and Jack

sym·bi·o·sis (smb-ss, -b-) n. pl. sym·bi·o·ses (-sz) 1. Biology A close, prolonged association between two or more different organisms of different species that may, but does not necessarily, benefit each member. 2. A relationship of mutual benefit or dependence. [Greek sumbisis, companionship, from sumbioun, to live together, from sumbios, living together : sun-, syn- + bios, life; see gwei- in Indo-European roots.] symbi·otic (-tk), symbi·oti·cal (--kl) adj. symbi·oti·cal·ly adv.

The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved

Dad and Jack have a symbiotic relationship as they travel in London: Dad knows all the history and Jack can navigate the tube.