[? corruption of BASE-STONE: cf. base for bay in prec.] A stone laid on the surface of the ground as part of the foundation of a slight building.

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1845.  Williams, in Jrnl. R. Agric. Soc., VI. I. 45. The tenant has the right to remove … any buildings put up by himself on ‘bay stones,’ where the buildings do not enter into the ground.

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