padreru : uncle (paternal)
The Illunse word for uncle (paternal uncle, father's brother) is padreru.
This word is a mixture of the Latin word for uncle (paternal uncle, father's brother) which is patruus, and the Old English word for uncle (paternal) which is fædera which I transliterate to faedera.
Note that both the Latin and the Old English words for uncle (father's brother) begin similar to their word for father. In Illunse my word for father is pader.
No aunt or uncle in Tolkien's words. I couldn't find Quenya or Sindarin words for aunt or uncle.