brink vs threshold

brink and threshold both are nouns.

Word	Noun	Adjective	Verb	Adverb
brink	Yes	No	No	No
threshold	Yes	No	No	No

As nouns, brink and threshold are synonyms defined as:

Other synonyms of brink include verge.

brink (noun)	threshold (noun)
the limit beyond which something happens or changes	the sill of a door; a horizontal piece of wood or stone that forms the bottom of a doorway and offers support when passing through a doorway
the edge of a steep place	the entrance (the space in a wall) through which you enter or leave a room or building; the space that a door can close
a region marking a boundary	the smallest detectable sensation
	a region marking a boundary
	the starting point for a new state or experience