Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

protactinium

play
noun prot·ac·tin·i·um \ˌprō-ˌtak-ˈti-nē-əm\

Definition of protactinium

  1. :  a shiny radioactive metallic element of relatively short life — see element table



Origin of protactinium

New Latin


First Known Use: 1918


Medical Dictionary

protactinium

play
noun prot·ac·tin·i·um \ˌprōt-ˌak-ˈtin-ē-əm\

Medical Definition of protactinium

  1. :  a shiny metallic radioelement of relatively short life—symbol Pa; see element table



Variants of protactinium

also pro·to·ac·tin·i·um \ˌprōt-ō-\play

Learn More about protactinium


Seen and Heard

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

WORD OF THE DAY

February 7, 2016

a slight offense

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image1037863653

Which of the following refers to thin, bending ice, or to the act of running over such ice?

pince-nez spindrift kittly-benders duvet
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

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

TAKE THE QUIZ