leatherback turtle vs leathery turtle

leatherback turtle and leathery turtle both are nouns.

Word	Noun	Adjective	Verb	Adverb
leatherback turtle	Yes	No	No	No
leathery turtle	Yes	No	No	No

As nouns, leatherback turtle and leathery turtle are synonyms defined as:

leatherback turtle and leathery turtle: wide-ranging marine turtle with flexible leathery carapace; largest living turtle

Other synonyms of leatherback turtle include Dermochelys coriacea, leatherback.

leatherback turtle (noun)	leathery turtle (noun)
wide-ranging marine turtle with flexible leathery carapace; largest living turtle	wide-ranging marine turtle with flexible leathery carapace; largest living turtle