The word "Artiad" is spelled using the International Phonetic Alphabet as /ɑrˈtaɪəd/. This word may not be familiar to many people, as it is a coined term referring to a period of roughly five years. The spelling of "Artiad" may seem unusual, but it reflects the word's origin in the Greek "artios," meaning "even number." The -iad suffix is a common way of indicating a period or span of time, and "Artiad" is used to refer to a period starting with a year ending in 2 or 3, and lasting for five years.
In chemistry, an element of even valence, a dyad, tetrad, or hexad; see perissad.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.