It would seem that our ancestors had just as many variants for ‘the smallest room’ as today’s folk.
Among the words for a ‘privy’ listed in Bosworth and Toller - apart from ‘gang-ern’ are ‘ears-gang‘, ‘forþ-gang‘, ‘gang/geng’, ‘genge’, ‘grepe‘, ‘fel-tun‘, ‘forþ-gang‘,‘gang-pyt(t)’, ‘gang-setl‘, ‘gang-tun’, ‘gold-hord-hus’ and ‘ut-gang’.
The actual seat on which you might sit was called a ‘gang-setl’ or ‘gang-stol’.
The unfortunate cleaner of the place was called a ‘gang-feormere’.
The lowermost deck of the ark was described as containing the ‘gangpyt’ and ‘myxen’ interpreted in Bosworth & Toller as the privy and dunghill respectively.
‘Earsgang is - according to B&T, used in the leechdoms both as the place of excretion (twice) and the act of excretion.