In Kent this was spelled foss ‘when I were a lad’. and meant ditch or even a “hole in the ground”. This is what I think is an accurate representation of the pronunciation. I will leave BelM to describe a fosse septique – I remember my father installing one in France, hence know this connection!

I would be pretty sure that hythe is a word of Old English extraction – seem to vaguely remember coming across something about this in connection to Alfred’s time. The only version I actually know about is the wonderful little steam railway I used to adore as a kid:

http://www.nlewis.freeserve.co.uk/rlyromney.html