Rare term for the front door of a building. In modern Japanese, 玄関の戸 or 正面の扉 are far more common.
In old Japanese houses, opening the front door led directly to the earthen floor area.
Compound of 表 (おもて, 'front') and 戸 (と, 'door'). The reading おもてど is a straightforward combination; the word is rare in modern usage.