From Bushwalk Australia
Noun: A shallow flat section of a waterway (river, creek, etc) suitable for wading through.
Verb: To cross a waterway by wading.
If a creek or river needs to be crossed, and there is no formal bridge and no suitable fallen log to use as a bridge, and there are insufficient stepping stones protruding from the water, then it may be necessary to wade through the water. The term 'ford' can refer both to wading through the water, as well as to a suitable location for wading through the water.
Fording a creek or river will often result in boots full of very cold water which is to be expected on many walks in Tasmania. However, a good set of well fitted gaiters and a quick crossing of a narrow and shallow waterway can sometimes reduce or even prevent water from entering the boots.
Note that if a waterway is crossed by swimming because the water is too deep for wading, that is not referred to as a ford.
Fording can be very dangerous. Even if the water is only knee deep, the current can be very powerful, and the bed of the river or creek can be uneven and slimy.