A set ot items.
One is the biggest: larger than al the others.
All the others are smalled than this one (the biggest one).
One is the smallest.
All the others are bigger than the smallest one.
.
They may all be big or small, depending on your perspective.
.
These houses in this development are all big by modern standards, all bigger than the house we saw yesterday, but this one here is the biggest of them all.