Salisbury railway station (XSR) sits in Wiltshire, England, and it is a train station, not an airport, so the plain answer to does Salisbury have an airport lounge is no: there is no commercial airport at Salisbury to operate one. Salisbury's own claim to fame is Salisbury Cathedral and its medieval close, a stop worth the visit in its own right rather than a staging post with any air-side amenities to speak of. The real lounge picture for travellers passing through Salisbury belongs to the airports they are actually flying from, most commonly London Heathrow (LHR) or Bristol Airport (BRS), both reachable from Salisbury by rail and connecting coach or car.
Heathrow, as one of the world's busiest hub airports, carries an extensive lounge network across its terminals, including airline lounges tied to British Airways and its partner carriers, plus Priority Pass and credit-card lounge coverage that varies by terminal and by specific lounge. Bristol Airport, the closer regional option for many Wiltshire travellers, has a smaller lounge footprint typical of a UK regional airport, generally built around a single pay-in or credit-card lounge rather than Heathrow's terminal-by-terminal spread.
Because coverage at both airports shifts by terminal, by airline, and by card issuer, do not assume a specific lounge or network applies until you check the current listing for whichever airport, Heathrow or Bristol, your flight actually departs from. Priority Pass and premium-card lounge benefits in particular are worth confirming close to your travel date, since terminal moves and network changes happen at busy UK airports more often than travellers expect.
For most people asking about a salisbury airport lounge, the honest answer starts and ends with geography: Salisbury itself has none, and the lounge question belongs to Heathrow or Bristol, whichever gateway is on your itinerary. Plan your access around that airport's current terms rather than around the station you are passing through.