Dictionary
Thesaurus
Medical
Scrabble®
Spanish Central
Browse DictionaryBrowse Thesaurus
Get our free apps!iPhone•iPad•Android
Games
Word of the Day
Video
Blog: Words at Play
My Faves
Dictionary

sis

noun \ˈsis\

Definition of SIS

:  sister —usually used in direct address
See sis defined for English-language learners
ADVERTISEMENT

First Known Use of SIS

1656

Rhymes with SIS

bis, bliss, bris, cis, cuisse, dis, Dis, hiss, kiss, miss, Swiss, this, vis, wis

SIS

abbreviation

Definition of SIS

Secret Intelligence Service (British)

Browse

4 ENTRIES FOUND:
  1. sis
  2. si
  3. -sis
  4. -ses
Next Word in the Dictionary: -sisPrevious Word in the Dictionary: sirventeAll Words Near: sis
ADVERTISEMENT
10 Charming Words for Nasty People
Put-downs with flair
Learn More
When "Literally" isn't, well, literal
How to use a word that (literally) drives some people nuts.
Watch Now
Know what this is?
Test your vocab with our fun, fast game
Go Play
Fear of cats?
Ailurophobia, and 9 other unusual fears
Learn More
Join Us
Merriam-Webster
on Facebook
Merriam-Webster
on Twitter
Bookstore: Digital and Print
Merriam-Webster references for Mobile, Kindle, print, and more.
See All
Other Merriam-Webster Dictionaries