BT BB 4a(38) : אינמי דפנינהו חד לרשותו‏ : if also one of them cleared (the fallen bricks) into his property
See the entire entry for pny vb. to turn

BT BB 4a(38) :דנפל לרשותא דחד מיני׳‏ : it fell into the domain of one of them
See the entire entry for rəšū, rəšūṯā n.f. control