sliver vs fleck

sliver and fleck both are nouns.

Word	Noun	Adjective	Verb	Adverb
sliver	Yes	No	Yes	No
fleck	Yes	No	Yes	No

As nouns, fleck is a hypernym of sliver; that is, fleck is a word with a broader meaning than sliver:

Other hypernyms of sliver include bit, chip, flake, scrap.

sliver (noun)	fleck (noun)
a thin fragment or slice (especially of wood) that has been shaved from something	a small contrasting part of something
a small thin sharp bit of wood or glass or metal	a small fragment of something broken off from the whole

sliver (verb)	fleck (verb)
break up into splinters or slivers	make a spot or mark onto
form into slivers
divide into slivers or splinters