| instrument(noun, person, means, agent, channel) |
| judge(noun, person, authority, advocate, expert) |
| mean(noun, means, middle, midway, midpoint) |
| referee(noun, authority, judge, expert, court) |
| vehicle(noun, person, end, means, agent) |
| agency(noun, means, agent, channel, medium) |
| arbiter(noun, authority, judge, expert, court) |
| intervening(adjective, middle, interposition) |
| medial(adjective, mean, middle, midway, midpoint) |
| messenger(noun, person, mark, contact, representative) |
| middle(adjective, mean, midway, midpoint, transitional) |
| peacemaker(noun, authority, advocate, judge, expert) |
| umpire(noun, authority, advocate, judge, expert) |
| centre |
| halfway(adjective, adverb) |
| organ(noun, person, means, channel, medium) |
| proxy(noun, agent, substitute, representative, operative) |
| substitute(noun, agent, representative, operative, manager) |
| center(adjective, mean, middle, midway, midpoint) |
| channel(noun, person, means, medium, arbitrator) |