Siamese twin

noun

: one of a pair of congenitally united twins

Word History

Etymology

from Chang †1874 and Eng †1874 congenitally united twins born in Siam

First Known Use

1829, in the meaning defined above

Time Traveler
The first known use of Siamese twin was in 1829

Dictionary Entries Near Siamese twin

Siamese fighting fish

Siamese twin

Siam, Gulf of

See More Nearby Entries 

Cite this Entry

“Siamese twin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Siamese%20twin. Accessed 25 Apr. 2024.

Copy Citation

Share

Kids Definition

Siamese twin

noun
: either of a pair of human or animal twins born joined together

Medical Definition

Siamese twin

noun
Si·​a·​mese twin ˈsī-ə-ˌmēz- How to pronounce Siamese twin (audio) -ˌmēs- How to pronounce Siamese twin (audio)
: either of a pair of conjoined twins

More from Merriam-Webster on Siamese twin

Britannica.com: Encyclopedia article about Siamese twin

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See All

More Commonly Misspelled Words

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Absent Letters That Are Heard Anyway

How to Use Accents and Diacritical Marks
See All

Popular in Wordplay

See All

The Words of the Week - Apr. 19

10 Words from Taylor Swift Songs (Merriam's Version)

9 Superb Owl Words

10 Words for Lesser-Known Games and Sports

Your Favorite Band is in the Dictionary
See All

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game You can make only 12 words. Pick the best ones!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A crossword with a twist
winning words from the national spelling bee logo
Spelling Bee Quiz Can you outdo past winners of the National Spelli...