What does ergo mean?
Ergo is a formal adverb and conjunction meaning "therefore" or "consequently," used to mark that a statement follows logically from what has just been said. It derives directly from Latin ergo, which served the same inferential function in classical rhetoric and philosophy, and it entered English in scholarly writing during the early modern period. Its most famous appearance is in Descartes's dictum cogito, ergo sum — "I think, therefore I am" — which has kept the word alive in popular culture well beyond academic circles. In modern usage, ergo signals careful reasoning, but it also lends itself to wry or tongue-in-cheek effect when dropped into casual conversation, giving an ordinary deduction an air of mock formality. Writers tend to place it after a semicolon or comma, as in "the evidence is thin, ergo the case will fail." Though interchangeable with therefore or hence, it is rarer, more literary, and instantly recognizable — making it a compact way to sound deliberate and precise.
Therefore; consequently — introducing what follows logically from what has been stated.
"The bridge inspection was overdue, ergo the closure was inevitable."
Usually placed mid-sentence after a comma or semicolon; beginning a sentence with it is possible but less common.
For this reason; used to connect a premise to its logical conclusion.
"He had already eaten, so he declined dessert, ergo the extra portion went to waste."
As a conjunction it functions much like 'so' or 'thus' but at a markedly higher register.
Descartes compressed all of human certainty into three words — cogito, ergo sum: I think, therefore I am.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of ergo
Ergo comes straight from Latin ergo, meaning "therefore," where it functioned as an inferential particle in classical argument. English adopted it in scholarly and philosophical writing during the late 16th and early 17th centuries, retaining both its Latin form and meaning unchanged. Its enduring fame owes much to René Descartes's 1637 formulation cogito, ergo sum. It shares its inferential role with Latin-derived siblings like "hence" and "therefore," though those came through native Germanic roots rather than Latin.
How ergo is actually used
Ergo is distinctly formal and often carries a slightly playful or ironic tone in everyday speech, where it can sound mock-erudite. It appears most naturally in written argument, philosophy, logic, and humor. It typically follows a semicolon or comma rather than beginning a sentence.
Easily confused with ergo
"Ego" refers to a person's sense of self or self-esteem (from Latin for "I"), while "ergo" means "therefore" — despite their visual similarity they are entirely unrelated in meaning.