thorn

UK: /ˈθɔːn/ US: /θɔrn/ ,'thorn': (thôrn); 'Thorn': (tôrn)

WordReference Random House Learner's Dictionary of American English © 2025

thorn /θɔrn/   n. 

1. Botany a hard, sharp point growing out on a plant:
   [countable] Roses have thorns.
2. Plant Biology a tree, bush, or shrub having such sharp points:
   [uncountable] rows of thorn.
   [countable] to cut down a few thorns.
3. a source or cause of continual annoyance:
   [countable] A noisy neighbor can be a thorn in one's side.

thorn•y, adj., -i•er, -i•est. 

WordReference Random House Unabridged Dictionary of American English © 2025

thorn  (thôrn), n. 

1. Botany a sharp excrescence on a plant, esp. a sharp-pointed aborted branch;
   spine;
   prickle.
2. Plant Biology any of various thorny shrubs or trees, esp. the hawthorns belonging to the genus Crataegus, of the rose family.
3. the wood of any of these trees.
4. Linguistics a runic character (þ), borrowed into the Latin alphabet and representing the initial th sounds in thin and they in Old English, or thin in modern Icelandic.
5. something that wounds, annoys, or causes discomfort.
6. thorn in one's side or flesh, a source of continual irritation or suffering:
   That child is a thorn in the teacher's side.

v.t. 

7. to prick with a thorn;
   vex.

• bef. 900; Middle English (noun, nominal), Old English; cognate with Dutch doorn, German Dorn, Old Norse thorn, Gothic thaurnus

thorn′less, adj. 
thorn′like′, adj. 

Thorn  (tôrn), n. 

1. Place Names German name of Torun. 

Collins Concise English Dictionary © HarperCollins Publishers::

thorn / θɔːn/ noun

1. a sharp pointed woody extension of a stem or leaf
   Compare prickle1
2. any of various trees or shrubs having thorns, esp the hawthorn
3. a Germanic character of runic origin Þ used in Old and Modern Icelandic to represent the voiceless dental fricative sound of th, as in thin, bath. Its use in phonetics for the same purpose is now obsolete
   See theta
4. this same character as used in Old and Middle English as an alternative to edh, but indistinguishable from it in function or sound
   Compare edh
5. a source of irritation (esp in the phrases a thorn in one's sideorflesh)

Etymology: Old English; related to Old High German dorn, Old Norse thorn

ˈthornless adjective

Collins Concise English Dictionary © HarperCollins Publishers::

Thorn / toːrn/ noun

1. the German name for Toruń