quarterly

Short definition from Wiktionary

Adjective

1. 1
   Occurring once every quarter year (three months); taking place quarter-yearly.
2. 2
   (of a coat of arms) Divided into four parts crosswise.

Noun

1. 1
   A periodical publication that appears four times per year.

Adverb

1. 1
   Once every quarter year (three months).
2. 2
   In the four, or in two diagonally opposite, quarters of a shield.