Semi- is a numerical prefix meaning "half". The prefix alone is often used as an abbreviation when the rest of the word (the thing which half of is being described) is clear from context.

12 hours ago · Local News 1 dead after crash involving semi on Route 23 in south Columbus All lanes are closed on Route 23 North at London-Groveport Road and on Route 23 South at Rathmell Road.

Aug 19, 2025 · According to Columbus Fire Chief Jeffrey Geitter, two tractor trailers collided on I-70 East, between Hilliard Rome Road and the I-270 interchange. Traffic was backed up several miles, …

Aug 9, 2025 · Interstate 270 southbound near the U.S. 33 interchange has fully reopened nearly 11 hours after a fatal crash involving a tractor-trailer and a van on Columbus' Southeast Side.

Aug 19, 2025 · Authorities say the driver of one of the semis was blinded by the sun and rear-ended the other semi. That semi was carrying batteries, and a leak occurred following the crash.

Semi - is a combining form used like a prefix meaning “half.” In some instances, it is used figuratively to mean "partially," "incompletely," or "somewhat."

semi- 1. A prefix that means "half," as in semicircle, half a circle. 2. A prefix that means "partly," "somewhat," or "less than fully," as in semiconscious, partly conscious.