What does coetaneously mean?
Coetaneously is a formal adverb meaning “at the same time” or “simultaneously.” It is used when two or more actions, events, or states occur or exist in parallel: “The two recordings began coetaneously.” The word is chiefly literary, technical, or historical in tone, and its rarity gives it a distinctly learned or emphatic quality. In ordinary modern English, “simultaneously” is usually the natural choice, while “coetaneously” can add precision by emphasizing exact coincidence. The term comes from the adjective “coetaneous” and ultimately from Latin “coetaneus,” meaning “of the same age” or “contemporary.” Although it sounds ornate, its meaning is straightforward and useful in descriptions of synchronized systems, experiments, performances, or historical events. It is especially effective when the fact that two occurrences coincide is itself significant, though it can sound overformal in casual conversation.
adverbAt the same time; simultaneously.
- At the same time as another event or action.
"The two experiments were conducted coetaneously to minimize environmental differences."
"The two clocks struck coetaneously at midnight."
"The witnesses gave their accounts coetaneously, each describing the same moment from a different position."
Its Latin ancestor meant “of the same age”: simultaneity began as a family resemblance.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does coetaneously come from?
The adverb was formed in English from “coetaneous” with the suffix “-ly.” “Coetaneous” comes from Latin “coetaneus,” meaning “of the same age” or “contemporary,” formed from “co-” meaning “together” and a form related to “aetas,” meaning “age.” It belongs to the same broad Latin family of words expressing simultaneity that includes “cotemporary” and “contemporaneous.”
Related word forms
How coetaneously is actually used
This is a formal, literary, and relatively uncommon word. In everyday modern English, “simultaneously” is usually more natural.
Easily confused with coetaneously
Contemporaneously means at the same period of time, whereas coetaneously more directly emphasizes two events occurring at the same moment.