Milton Bradley in his glossary to Improve Fast in Go wrote:NAKADE (nah-kah-day): The placement of stones inside an opposing group to reduce the shape to one eye.
Cassandra in her glossary to Igo Hatsuyôron 120 wrote:"dead bulky shape" / "move that occupies this shape's vital point".
Robert Jasiek here wrote:"Simply speaking, a NAKADE is a lake, so that
1. the defender can fill all but one of its intersections,
2. the defender cannot partition it and
3. there cannot be a seki or ko in it."
Robert Jasiek elsewhere wrote:A _nakade_ is a region of connected intersections so that
* if each intersection adjacent to the region is occupied by the defender's stone with an outside liberty and the players play only within the region, the defender moving first can necessarily fill all but one of the intersections of the region,
* if each intersection adjacent to the region is occupied by the defender's stone with an outside liberty and the players play only within the region, the defender moving first cannot necessarily permanently partition it into at least two regions,
* if the initial position is the starting position, the players may play anywhere and either player tries to prevent the other's new independent life, neither player can force occurrence of a seki or ko ban involving the region, and
* if each intersection adjacent to the region is occupied by the defender's stone without any outside liberty, the players play only within the region, and either player tries to prevent the other's new independent life, neither player can force occurrence of a seki or ko ban involving the region.
I personally am more willing to forgive less than accurate definitions than I am to forgive less than comprehensible formulations. To some extent, this is a reflection of my go understanding, but the more linguistic clarity, the more likely I am to mentally make note of a concept.
Above, Cassandra asks what problems are created by her own admittedly inconsistent use of the word in her book. I say: fewer than caused by a precise definition that is so formulated that one opts out of trying to figure out it's meaning.