'Hackney' probably means Haca's ey, raised ground in the marshes.
The name is older than the Norman Conquest, and its meaning is not certain. Ey meant an island or dry ground in marshland, perhaps beside the Lea or where Hackney Brook met Pigwell Brook, near today's Hackney Central. It appears in records from 1198, and as Hakney in 1231. Earlier stations here were called simply Hackney; Hackney Central dates from 1980.