What is the X in X-mas?
late 13c., "thing that rolls;" early 15c., "rolling pin," agent noun from roll (v.). Meaning "hair-curler" is attested from 1795. Roller derby is from 1936 (see derby); roller hockey from 1926. Disparaging religious term holy roller is attested from 1842, American English, from the alleged rolling in the church aisles done by those in the Spirit.
any of about 12 species of Old World birds constituting the family Coraciidae (order Coraciiformes), named for the dives and somersaults they perform during the display flights in courtship. The family is sometimes considered to include the ground rollers and cuckoo rollers. Rollers inhabit warm regions from Europe and Africa to Australia.