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Core Words Familarize yourself with the 'core words'.
Compounds Expand your vocabulary by studying more complex words built by the 'core words'.
Etymology Explore the origin of the 'core words'.

{n}	boundary	(dividing line or location between two areas)	Grenze {f}
{n}	boundary	((topology) the set of points in the closure, not belonging to the interior)	Rand {m}