Heimdall vs Heimdallr

Heimdall and Heimdallr both are nouns.

Word	Noun	Adjective	Verb	Adverb
Heimdall	Yes	No	No	No
Heimdallr	Yes	No	No	No

As nouns, Heimdall and Heimdallr are synonyms defined as:

Heimdall and Heimdallr: (Norse mythology) god of dawn and light; guardian of Asgard

Other synonyms of Heimdall include Heimdal.

Heimdall (noun)	Heimdallr (noun)
(Norse mythology) god of dawn and light; guardian of Asgard	(Norse mythology) god of dawn and light; guardian of Asgard