Q: You might be able to save me from a Google failure to find a linguistic reason for the expression “brought back from the dead.” Why does it have a definite article? Wondering about this is making my arm twitch.
A: Since Anglo-Saxon times, the definite article has been used before an adjective to create a noun phrase with a plural sense, as in “the poor,” “the rich,” “the lame,” “the sick,” “the naked,” and “the dead.”
In such phrases, “the poor” means “the people who are poor” or “those who are poor,” while “the rich” means “the people who are rich” or “those who are rich.”
The earliest example of this usage in the Oxford English Dictionary is a reference to ð worold-wisan (the worldly wise) from Pastoral Care (c. 897), King Aelfred’s Old English translation of a Latin treatise by Pope Gregory I.
Here’s a modern English example from Shelley’s 1819 poem Rosalind and Helen: “He was a coward to the strong: / He was a tyrant to the weak.”
The OED’s earliest example for “the dead,” the specific phrase you’ve asked about, is a reference to þe deade (the dead) in a document from around 1175 in the Lambeth Manuscript, a collection of late Old English sermons.
Finally, here’s an Oxford example from Shakespeare’s Julius Caesar (c. 1599): “I will not do them wrong; I rather choose / To wrong the dead, to wrong myself and you.” (We’ve expanded Antony’s lines.)
If you’d like to read more, we had a post six years ago about the idiomatic use of “the” with the names of things that wouldn’t appear to need an article (or that could use the article “a” instead).