thorn

noun

ˈthȯrn 

often attributive

1

a

: a sharp rigid process on a plant

especially : one that is a short, indurated, sharp-pointed, and leafless modified stem compare prickle, spine

b

: any of various sharp spiny structures on an animal

2

: a woody plant bearing sharp impeding processes (such as prickles or spines)

especially : hawthorn

3

: something that causes distress or irritation

—often used in the phrase thorn in one's side

4

: the runic letter þ used in Old English and Middle English to represent either of the fricatives \th\ or \t͟h\ and in Icelandic to represent \th\

thorned

ˈthȯrnd 

adjective

thornless

ˈthȯrn-ləs 

adjective

thornlike

ˈthȯrn-ˌlīk 

adjective

Synonyms of thorn

• headache
• nuisance
• irritant
• frustration
• rub

Examples of thorn in a Sentence

your constant questions are a thorn in my side

Recent Examples on the Web

Baydon's tattoo needle is a spiky thorn of a pomelo tree attached to a thin bamboo reed. — Marisol Delarosa, Condé Nast Traveler, 20 Aug. 2026

That would be, of course, the dozen attorneys general led by California’s Rob Bonta, whose antitrust lawsuit last month seeking to block the merger has been a thorn in Ellison’s side. — Steven Zeitchik, HollywoodReporter, 19 Aug. 2026

But the Vulcan program has been a thorn in ULA’s plans to ramp up launches. — Richard Tribou, The Orlando Sentinel, 17 Aug. 2026

Their kickers’ health and performance for years have been one of the thorns in the team’s side. — Pat Leonard, New York Daily News, 13 Aug. 2026

Word History

Etymology

Middle English, from Old English; akin to Old High German dorn thorn, Sanskrit tṛṇa grass, blade of grass

First Known Use

before the 12th century, in the meaning defined at sense 2

Phrases Containing thorn

• a thorn in the/someone's flesh/side
• Christ's-thorn
• Christ-thorn
• Jerusalem thorn
• thorn apple

Rhymes for thorn

• borne
• bourn
• bourne
• corn
• morn
• morne
• mourn
• porn
• scorn
• shorn
• sworn
• torn

Kids Definition

thorn

noun

ˈthȯ(ə)rn 

1

: a woody plant bearing sharp processes (as prickles or spines)

especially : hawthorn

2

: a sharp stiff process on a plant

especially : a stem modified into a short, stiff, and leafless sharp point

3

: something or someone that causes distress or irritation

—often used in the phrase thorn in one's side

thorned

ˈthȯ(ə)rnd 

adjective

thornless

ˈthȯ(ə)rn-ləs 

adjective