SWI may refer to: Places: Switzerland (this is not the ISO 3166-1 code, which is CHE) Swindon railway station (National Rail code SWI), serving Swindon, Wiltshire, United Kingdom In science and technology: SWI-Prolog, a free implementation of the programming language Prolog Susceptibility weighted imaging, in magnetic resonance imaging (MRI) used in medical contexts Software interrupt, an interrupt routine in a computer operating system SWI, an assembler mnemonic to perform a software interrupt on the ARM microprocessor family Szilagyi Waterspout Index Other uses: Swissinfo, a service of the Swiss Broadcasting Corporation Structured Word Inquiry, a pedagogical technique involving the scientific investigation of the spelling of words