Definition of RI

1 refractive index
2 Rhode Island

Keep scrolling for more

More Definitions for RI

Kids Definition of RI

Rhode Island

More from Merriam-Webster on RI

Spanish Central: Translation of RI

Comments on RI

What made you want to look up RI? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

using a distributed computer network

Get Word of the Day daily email!

Test Your Vocabulary

Time Traveler Quiz: Which Word Came First?

  • time traveler quiz which word came first
  • Which came first?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

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