rail fence vs split-rail fence

rail fence and split-rail fence both are nouns.

Word	Noun	Adjective	Verb	Adverb
rail fence	Yes	No	No	No
split-rail fence	Yes	No	No	No

As nouns, rail fence and split-rail fence are synonyms defined as:

rail fence and split-rail fence: a fence (usually made of split logs laid across each other at an angle)

rail fence (noun)	split-rail fence (noun)
a fence (usually made of split logs laid across each other at an angle)	a fence (usually made of split logs laid across each other at an angle)