down vs turn

down and turn both are nouns.

Word	Noun	Adjective	Verb	Adverb
down	Yes	Yes	Yes	Yes
turn	Yes	No	Yes	No

As nouns, turn is a hypernym of down; that is, turn is a word with a broader meaning than down:

Other hypernyms of down include play.

down (noun)	turn (noun)
(American football) a complete play to advance the football	the act of changing or reversing the direction of the course
soft fine feathers	the act of turning away or in the opposite direction
fine soft dense hair (as the fine short hair of cattle or deer or the wool of sheep or the undercoat of certain dogs)	taking a short walk out and back
(usually plural) a rolling treeless highland with little soil	a favor for someone
	(game) the activity of doing something in an agreed succession
	turning or twisting around (in place)
	a short performance that is part of a longer program
	a movement in a new direction
	an unforeseen development
	a circular segment of a curve
	(sports) a division of a game during which one team is on the offensive
	a time period for working (after which you will be relieved by someone else)

down (adjective)	turn (adjective)
being or moving lower in position or less in some value
filled with melancholy and despondency
extending or moving from a higher to a lower place
becoming progressively lower
not functioning (temporarily or permanently)
lower than previously
shut
being put out in a game of baseball
understood perfectly

down (verb)	turn (verb)
improve or perfect by pruning or polishing	twist suddenly so as to sprain
bring down or defeat (an opponent)	change to the contrary
drink down entirely	go sour or spoil
eat up completely, as with great appetite	pass into a condition gradually, take on a specific property or attribute; become
cause to come or go down	undergo a transformation or a change of position or action
shoot at and force to come down	change color
	become officially one year older
	have recourse to or make an appeal or request for help or information to
	direct at someone
	shape by rotating on a lathe or cutting device or a wheel
	let (something) fall or spill from a container
	alter the functioning or setting of
	cause (an object) to assume a crooked or angular form
	to break and turn over earth especially with a plow
	to change orientation or direction
	cause to move around a center so as to show another side of
	cause to move around or rotate
	pass to the other side of
	move around an axis or a center
	to send or let go
	cause to move along an axis or into a new direction
	channel one's attention, interest, thought, or attention toward or away from something
	get by buying and selling
	accomplish by rotating
	undergo a change or development
	cause to change or turn into something different;assume new characteristics

down (adverb)	turn (adverb)
spatially or metaphorically from a higher to a lower level or position
away from a more central or a more northerly place
paid in cash at time of purchase
in an inactive or inoperative state
to a lower intensity
from an earlier time