Hart vs hartley

Hart and hartley both are nouns.

Word	Noun	Adjective	Verb	Adverb
Hart	Yes	No	No	No
hartley	Yes	No	No	No

As nouns, Hart and hartley are synonyms defined as:

Hart and hartley: a logarithmic unit which measures information or entropy, based on base 10 logarithms and powers of 10.

Other synonyms of Hart include ban, dit.

Hart (noun)	hartley (noun)
United States lyricist who collaborated with Richard Rodgers (1895-1943)	a logarithmic unit which measures information or entropy, based on base 10 logarithms and powers of 10.
United States playwright who collaborated with George S. Kaufman (1904-1961)
a logarithmic unit which measures information or entropy, based on base 10 logarithms and powers of 10.