παρένθεσις

Parenthesis comes from the Greek parentithenai: para (beside) + en (in) + tithenai (to place). In ancient rhetoric, a parenthesis was not a mark but a figure of speech — an interruption inserted into a sentence that was grammatically complete without it. The speaker broke the flow to add a comment, a qualification, a digression, and then resumed as if nothing had happened.

Medieval scribes sometimes marked these insertions with a pair of curved strokes or commas, but the rounded brackets we now call parentheses did not appear in print until the late 1400s. The Venetian printers — Aldus Manutius and his contemporaries — experimented with various enclosure marks. By the 1500s, the paired curves ( ) had become standard in European typography.

Erasmus, in his 1512 rhetoric manual *De Copia*, recommended parenthetical remarks as a way to enrich prose — but warned against excess. A parenthesis should feel like a natural aside, not a derailment. Renaissance writers took this advice selectively. Montaigne's *Essais* are famously digressive, with parenthetical thoughts nesting inside other parenthetical thoughts until the original sentence is nearly forgotten.

In the 20th century, parentheses found new homes. Mathematics uses them for grouping: (2 + 3) × 4. Programming languages use them for function calls: print("hello"). Emoticons turned them into smiles :) and frowns :(. The curved marks that once contained rhetorical asides now contain computational logic and human emotion, sometimes in the same message.