millstone vs albatross

millstone and albatross both are nouns.

Word	Noun	Adjective	Verb	Adverb
millstone	Yes	No	No	No
albatross	Yes	No	No	No

As nouns, millstone and albatross are synonyms defined as:

millstone and albatross: (figurative) something that hinders or handicaps

millstone (noun)	albatross (noun)
one of a pair of heavy flat disk-shaped stones that are rotated against one another to grind the grain	large web-footed birds of the Southern Hemisphere having long narrow wings; noted for powerful gliding flight
any load that is difficult to carry	(figurative) something that hinders or handicaps
(figurative) something that hinders or handicaps