firs / furs / furze are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
firs: (noun) nonresinous wood of a fir tree. (noun) any of various evergreen trees of the genus Abies; chiefly of upland areas.
furs: (noun) the dressed hairy coat of a mammal. (noun) dense coat of fine silky hairs on mammals (e.g., cat or seal or weasel). (noun) a garment made of the dressed hairy coat of a mammal.
furze: NA
firs: f·ER·z
furs: f·ER·z
furze: NA
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)