Robert Grant was born in 1707, in Connecticut, United States. He married Bethiah Reed in 1729, in New London, Connecticut, United States.
Irish, English, and especially Scottish (of Norman origin): nickname from Anglo-Norman French graund, graunt ‘tall, large’ (Old French grand, grant, from Latin grandis), given either to a person of remarkable size, or else in a relative way to distinguish two bearers of the same personal name, often representatives of different generations within the same family.
English: from the rare Middle English (and Old English) personal name Grante or Grente.
Irish: in Ireland this is usually the Norman Scottish name (see 1 above), but it was also adopted for Irish Mag Raighne, see Graney .