movement vs saccade

movement and saccade both are nouns.

Word	Noun	Adjective	Verb	Adverb
movement	Yes	No	No	No
saccade	Yes	No	No	No

As nouns, saccade is a hyponym of movement; that is, saccade is a word with a more specific, narrower meaning than movement:

movement (noun)	saccade (noun)
a change of position that does not entail a change of location	a rapid, jerky movement of the eyes between positions of rest
the act of changing the location of something	an abrupt spasmodic movement
a series of actions advancing a principle or tending toward a particular end
the act of changing location from one place to another
the driving and regulating parts of a mechanism (as of a watch or clock)
a general tendency to change (as of opinion)
a major self-contained part of a symphony or sonata
a natural event that involves a change in the position or location of something
a group of people with a common ideology who try together to achieve certain general goals
an optical illusion of motion produced by viewing a rapid succession of still pictures of a moving object
a euphemism for defecation