birr / bur / burr 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. 👇
birr: (noun) the basic unit of money in Ethiopia; equal to 100 cents.
bur: (noun) seed vessel having hooks or prickles. (noun) small bit used in dentistry or surgery. (verb) remove the burrs from.
burr: (noun) rough projection left on a workpiece after drilling or cutting. (noun) United States politician who served as vice president under Jefferson; he mortally wounded his political rival Alexander Hamilton in a duel and fled south (1756-1836). (noun) rotary file for smoothing rough edges left on a workpiece.
birr: b·ER
bur: b·ER
burr: b·ER
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)