A between maid (nickname tweeny, also called hall girl particularly in the United States) was a female junior domestic worker in a large household with many staff.
[1] The position became largely defunct in the 20th century, as few households needed or could afford great retinues of domestic workers with the elaborate hierarchy of the past.
The term between maid came from the fact that her duties were split between the area of responsibilities of the housekeeper, butler and cook.
Parlour maids cleaned and tidied reception rooms and living areas in the mornings, and often served refreshments at afternoon tea, as well as sometimes serving dinner.
They tidied studies and libraries and, with footmen, answered bells calling for service.