A Hosier was a tradesman who manufactured and sold socks.
The history of Hosiery is laced with manipulations and intrigues, which are plainly evident in the 1663 Charter, in which King Charles II granted some 25 people the power over the business - for life - in return for a share in their revenues. One of these people was Mary Burton-Gulliver’s uncle-in-law (The father of her sister’s husband.)
It was a hard, masculine work. Using machines, as well as knitting by hand, Hosiery was a respected profession -- especially when one made a lot of money being one.
Though, unlike today, at that time machine-made silk stockings were more expensive than hand-knitted ones, since machines were not considered as reliable as they are considered today.