ris
- A rare or obsolete term referring to a branch or twig. nounHe picked up a ris from the ground to use as a walking stick.The bird perched on a ris, chirping merrily.
- An abbreviation for 'Remote Installation Services', a Microsoft technology for network-based installation of Windows operating systems. nounThe IT department used RIS to deploy the new software across all company computers.RIS simplifies the process of installing operating systems on multiple machines.