Settings > Lookups

Social > Accounts > Main > Industry

Yes. You can add an Industry Sector by accessing the Lookups screen and clicking on the Industry Sector lookup option.

Click Add in order to create a new one and fill in the required fields on the Lookup (Add/Edit) screen then Save. The new industry sector should now appear as an option for an Account.

Note: you cannot delete nor remove an existing Industry Sector, not any lookup.