All 4 Uses of

Dutch
in
The Mysterious Benedict Society

My parents were Dutch scientists, killed in a laboratory accident when I was a baby.
p. 140.7 *

Dutch = of the Netherlands

Nothing in the world less controllable than the sea, and yet the Dutch found a way to control it.†
p. 262.2

But since you're so proud of your home country, I think we'll also try Dutch.†
p. 461.9

Sticky, how do you spell 'control' in Dutch?†
p. 462.1

in dutch = of the Netherlands or its people

Definitions:

(1) (Dutch)
the people of the Netherlands (including Holland); or relating to them (including the name of their language)

Many people refer to the Netherlands as Holland -- which is more accurately the most populous region of the Netherlands. The Netherlands is best known for having 25% of its land below sea level.
(2) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

Less commonly, Dutch is used in a the phrase Dutch oven (a thick-walled cooking pot with a tight-fitting lid) or Dutch doors (a door divided in such a fashion that the bottom half may remain shut while the top half opens).