on-site adjective 1on site prepositional phrase 1 adjective1 •On a particular site or in a particular building, as opposed to at a remote site or factory.Our supplier offers on-site support. on site prepositional phrase1 •At the site of a job, or at the location of the customer of a product or service, as opposed to at the vendor's factory, office, or studio.If we can't figure out how to diagnose this problem remotely, we're going to have to go on site again.The final paint touch-ups will be performed on site, after installation.
