That's not "the" answer (in the sense of: the only correct answer), but it is an answer.
η διεύθυνση can be an address (like "1600 Pennsylvania Avenue NW, Washington, DC 20500") or it can mean management.
The thing they have in common is the direction that they give -- an address directs you to a place, and management directs a company.
Dropping the -ν is considered mandatory in the official rule. However, it'snot uncommon to see people not dropping it IRL. In the new tree all the translations showed are going to follow the rule, though (not dropping the ν will problably still be accepted as it's something common in written speech).