LawProse Lesson #171: “On” or “upon”?

On or upon? These prepositions are usually synonymous and used in virtually identical ways. The distinctions are primarily in tone and connotation. On — the shorter, simpler, more direct word — is generally preferable {the trial court’s decision was based on the parol-evidence rule} {service on a defendant} {the case centers on a 2006 contract} {the burden is on the plaintiff}. Upon is stylistically inferior when on will suffice — if only because it tends to sound stuffy. Yet upon is preferable in one circumstance: when it introduces a condition, occurrence, or event {upon a proper showing by the applicant, a license will be granted} {upon being served with interrogatories, the plaintiff called his lawyer} {he was arrested upon returning to the United States} {the voter left upon being told the polls were closed}. The sense “with little or no interval after” is often an important nuance of upon {the board may remove the officers for good cause shown upon a petition, notice, and hearing}. Upon is also imperative in stock phrases such as once upon a time and take it upon yourself. Stop yourself when you write upon and ask whether it’s introducing a condition, occurrence, or event. If not, use on. Your style will become fresher and more down-to-earth just by deleting two letters. Further reading: Garner’s Dictionary of Legal Usage 633, 917 (3d ed. 2011). Garner’s Modern American Usage 589, 834 (3d ed. 2009). Thanks to John Crouchley and Charles L. Warner for suggesting this topic.