Yes, I transcribed 'dau', as that is what the original handwritten page says .... but now I look more closely, Ann E. is 26 - and only 39 with the same forenames in the 1871 when married to Mr B - so I wonder if it is the same person, and should in fact be wife back in 1861??
If she IS Thomas' daughter as stated in the 1861, then given the ages of John & Alfred, and their stepson status in 1871, she may well be thier mother anyway.....