Solutions river that rises in the cairngorm mountains before flowing east to the north sea has 4 entries with similar clues

• 5-letter words
• forthA river that rises in central Scotland and flows through Stirling into the North Sea
• rhineRiver flowing from Switzerland, through Germany, to North Sea
• 6-letter words
• anduinIn J R R Tolkien's The Lord of the Rings , the great river, east of the Misty Mountains, on whose west bank is the Elvish land of Lothlorien
• 8-letter words
• aviemoreScottish winter sports centre in the Cairngorms