A freeholder owns the land itself. For example , the various colleges each own substantial bits of land in the city. But a lot of it has been let, leased, over the years. The leaseholder might have built an office block on it. But the lease for the block, built by him at his expense, might only give the leaseholder the right to be there for 66 years. When the 66 years are up, the whole block belongs to the college, because they own the land , as freeholders, and therefore own everything built on it And you get sub-lessees. The block might be let by the 66 year leaseholder to a company or floors of it different companies, all for terms less than his own lease