In coal-mining, this was a hole or depression set beneath the lowest landing in a shaft, where water gathered before draining away or being pumped to the surface.
A tenant was said to surrender an estate when he relinquished his interest in copyhold lands, yielding them directly to the lord of the manor, or via the lord to another person. The piece of straw was a symbol of the crops the land was capable of producing.
Spellings recorded elsewhere include ‘swally’ and swilly’, so they may derive from the dialect pronunciation of ‘swallow’, in the sense of a hole. In west Yorkshire it refers to a hollow place in the coal stratum, often filled with water.
The swingle was a sword-like implement used in the dressing of flax and hemp and it gave rise to both a verb and an adjective (OED); the ‘stock’ was a wooden board on which the fibres were beaten.