Right. I assumed they specifically meant a wave that occurred in an otherwise calmer sea.
I believe the highest non-tsunami wave on record was over 90 feet, and was recorded by a US Navy oiler (USS Rampao) in the Pacific in 1933 at 112 feet. I recall they were able to measure it using the height of the wave measured from a point on their deck to a point on their mast.
The largest wave of any kind seen by humans was in Alaska in 1958 at 1,720 feet when an earthquake caused a landslide into a bay.
“The largest wave of any kind seen by humans was in Alaska in 1958 at 1,720 feet when an earthquake caused a landslide into a bay.”
It was only about 100 feet high. Boats survived.