cocklebur vs cockleburr

cocklebur and cockleburr both are nouns.

Word	Noun	Adjective	Verb	Adverb
cocklebur	Yes	No	No	No
cockleburr	Yes	No	No	No

As nouns, cocklebur and cockleburr are synonyms defined as:

cocklebur and cockleburr: any coarse weed of the genus Xanthium having spiny burrs

Other synonyms of cocklebur include cockle-bur, cockle-burr.

cocklebur (noun)	cockleburr (noun)
any coarse weed of the genus Xanthium having spiny burrs	any coarse weed of the genus Xanthium having spiny burrs
burdock having heart-shaped leaves found in open woodland, hedgerows and rough grassland of Europe (except extreme N) and Asia Minor; sometimes cultivated for medicinal and culinary use