The Britannica Dictionary
mobile search
Home
Ask the Editor
Word of the Day
Quizzes
Core Vocabulary
Browse the Dictionary
×
Britannica Homepage
Ask the Editor
Word of the Day
Quizzes
Core Vocabulary
Browse the Dictionary
The Britannica Dictionary
third rail
1 ENTRIES FOUND:
third rail
(noun)
third rail
noun
third rail
noun
Britannica Dictionary definition of THIRD RAIL
[
singular
]
1
:
a metal rail on a train track that carries electric current to the train's motor
2
:
a difficult issue that politicians try to avoid talking about
Social Security is the
third rail
of American politics.
[+] more examples
[-] hide examples
[+] Example sentences
[-] Hide examples
ASK THE EDITOR
What are the plural forms of
check-in
,
passerby
, and
spoonful
?
See the answer »
QUIZZES
Vocabulary Quiz
Test your word power
Take the Quiz »
Name That Thing
Take our visual quiz
Test Your Knowledge »
WORD OF THE DAY
enamored
:
in a state in which you love, admire, or are very interested in something or someone
Learn More »