The word "rieth" is an archaic spelling of the word "reath" or "rath", meaning a circular fortification. It is pronounced as /rɛθ/ or "reth" in IPA phonetic transcription. The spelling "rieth" was common in Old and Middle English, and can still be found in some place names in the United Kingdom, such as "Braybrook Riethe" in Northamptonshire. However, the more modern spelling is "rath" in Irish and Scottish Gaelic, and "reath" in English.