Dictionary.com
Thesaurus.com

granduncle vs. great-uncle

[grand-uhng-kuhl] / ˈgrændˌʌŋ kəl /

noun

  1. an uncle of one's father or mother; a great-uncle.

[greyt-uhng-kuhl] / ˈgreɪtˌʌŋ kəl /

noun

  1. a granduncle.