1) No definition available
The OED has one reference to grandson in 1586 and a second in 1655. Grand-daughter is first on record in 1611 and grandchild in 1587. Those relationships are expressed in a variety of ways in early wills: 1541 I gyff unto John Lasynbe my soyn soyn ij kye, Whitwell
1549 I hartely deseryer him to be so good maister ... to George Lowfhows my sone sone, Marrick
1573 unto Elizabeth Lassells my doughters doughter whom I christened twentee marks, Walburn Hall.