Morphology: hendre+ the name Denni or Tenni
Phonetic: hen-dread-any
Traditionally, Welsh farms had dwellings for the summer months for the winter, the latter were known as "hendre" and were lower in the valley to shelter from the winter winds. This settlement gets its name from nearby Hendre-denny Hall, a grade 2 listed building, built near or on a farm site dating back at least to the early 14th century, when "Hendredeni" was listed as part of the property belonging to Gilbert de Clare, who built Caerphilly Castle. The name is recorded in 1746 as Tire finnon Denny and the name also appears in the place name Llandenny / Llandenni, to north of Usk in Monmouthshire (earlier Mathenni). Another possibility is that "deni or denny" comes from the Welsh word "denu", which means "to attract" and could therefore mean that the farm was in an attractive location.