Zero copula

Road signs commonly use zero copula (omitting the verb to be). This sign uses the sentence "road closed" as a nominal sentence to mean "the road is closed."

Zero copula, also known as null copula, is a linguistic phenomenon whereby the subject is joined to the predicate without overt marking of this relationship (like the copula to be in English). One can distinguish languages that simply do not have a copula and languages that have a copula that is optional in certain contexts.

Dropping the copula is also found, to a lesser extent, in English and many other languages, used most frequently in rhetoric, casual speech, non-standard varieties, road signs, and headlinese, the writing style used in newspaper headlines. Sometimes, these omissions cause unintended syntactic ambiguity.