Children's, Intermediate and Advanced Online English Dictionary & Thesaurus

Comprehensive
Dictionary Suite
Help
Help
Help
 
Advanced Dictionary    
Display options
Show syllables
Show Lookup History
Double-Click Lookup
  Show Spanish support
  Show Word Combinations
 
Pronunciation
Wordsmyth
  Phonics
  IPA
 
Entry formats
Standard
  Classic
 
Lookup History
protactinium

pro·tac·tin·i·um

protactinium

 
pronunciation:
pro taek tI ni m
part of speech: noun
definition: a very toxic radioactive chemical element of the actinide series that has ninety-one protons in each nucleus and that is a product of the radioactive decay of uranium. (symbol: Pa)