Doomsday and Watershed

Doomsday noun - (New Testament) day at the end of time following Armageddon when God will decree the fates of all individual humans according to the good and evil of their earthly lives.

Watershed and doomsday are semantically related. In some cases you can use "Watershed" instead a noun "Doomsday".

Watershed noun - A point in a chain of events at which an important change (as in one's fortunes) occurs.

Doomsday and watershed are semantically related. Sometimes you can use "Doomsday" instead a noun "Watershed".