TRIWEEKLY
Etymology
Adjective
triweekly (not comparable)
Occurring three times per week.
Occurring once every three weeks.
Published three times a week.
Noun
triweekly (plural triweeklies)
A publication published three times a week.
Source: Wiktionary
Tri"week`ly, a. Etym: [Pref. tri- + weekly.]
Definition: Occurring or appearing three times a week; thriceweekly; as, a
triweekly newspaper.
– adv.
Definition: Three times a week.
– n.
Definition: A triweekly publication.
Note: This is a convenient word, but is not legitimately formed. It
should mean occurring once in three weeks, as triennial means once in
three years. Cf. Biweekly.
Source: Webster’s Unabridged Dictionary 1913 Edition