settler vs sourdough

settler and sourdough both are nouns.

Word	Noun	Adjective	Verb	Adverb
settler	Yes	No	No	No
sourdough	Yes	No	No	No

As nouns, sourdough is a hyponym of settler; that is, sourdough is a word with a more specific, narrower meaning than settler:

settler: a person who settles in a new colony or moves into new country
sourdough: a settler or prospector (especially in western United States or northwest Canada and Alaska)

Other hyponyms of settler include Pilgrim, Pilgrim Father, pioneer, homesteader, nester, squatter.

settler (noun)	sourdough (noun)
a person who settles in a new colony or moves into new country	a settler or prospector (especially in western United States or northwest Canada and Alaska)
a clerk in a betting shop who calculates the winnings	a leaven of dough in which fermentation is active; used by pioneers for making bread
a negotiator who settles disputes