From OE 'geat' — originally meaning an opening or gap, not the barrier filling it; northern English '-gate' streets are from Old Norse 'gata' (road).
A hinged barrier used to close an opening in a wall, fence, or hedge; an entrance or passage.
From Old English 'geat' (plural 'gatu'), meaning a gate, door, or opening, from Proto-Germanic *gatą, from the PIE root *gʰed- meaning 'an opening, a gap.' The original sense was simply a hole or gap in a barrier — the physical door or barrier that fills it came later. Old Norse 'gat' (opening, passage) is cognate and contributed to the northern English and Scots word 'gate' meaning 'road' or 'way,' which survives in street names