In my mind a house coat is a garment worn over your clothes to protect them whilst doing household chores. A dressing gown is a garment you wear over your night clothes for extra warmth or to preserve your modesty if you sleep naked and have to get up in the night or wear if you’re ill.
1 Like
It’s dressing gown in this house! Though robe may also be acceptable
Dressing gown I would prefer
Dressing gown here