SINCE 1828

An Encyclopædia Britannica Company

custos morum

Latin noun phrase cus·tos mo·rum \ ˌku̇-stōs-ˈmȯr-u̇m \

Definition of custos morum

:guardian of morals :censor

Seen and Heard

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

show

WORD OF THE DAY

nuncupative

play

spoken rather than written

Words at Play

alt-59ea52ed7b96f

Learned Fools: On Names for Students

Where did we get 'freshman' and 'sophomore'?

alt-59e900afadac6

The Synonyms 'Discover' and 'Invent'

In the past, you could invent fruit.

alt-59e8c3440f453

I'll Have the Us(ual)

Shortening 'usual': easy to say, hard to spell

alt-59e77dc36c593

The Origins of 'Lobbyist'

From the front hallways to the back rooms

Ask the Editors

video-title-words-of-the-year-1066

Words of the Year: 1066

Or, Why Pig Meat is Called 'Pork' and Cow Meat is Called 'Beef'

How Often Is 'Biweekly'?

Don't get us started on 'bimonthly'

video-irregardless-grammar-peeve-blend-of-the-synonyms-irrespective-and-regardless

Irregardless

It is in fact a real word (but that doesn't mean you should use it).

video-moose-goose-weird-plurals

Weird Plurals

One goose, two geese. One moose, two... moose. What's up with that?

Word Games

one-green-toy-robot-amidst-many-red-toy-robots

The Exceptions Quiz III

Which of these things doesn't belong?

Take the quiz

knupfer-painting-solon-before-croesus

Forms of Government Quiz

Name that government! Or something like that.

Take the quiz

How Strong Is Your Vocabulary?

How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Take the quiz

Dictionary Devil

Dictionary Devil

The dictionary has been scrambled—can you put it back together?

Play the game