Merriam-Webster Collegiate Dictionary - quarterly

 I. adverb  Date: 14th century  1. in heraldic quarters or quarterings  2. at 3-month intervals  II. adjective  Date: 15th century  1. computed for or payable at 3-month intervals a ~ premium  2. recurring, issued, or spaced at 3-month intervals  3. divided into heraldic quarters or compartments  III. noun  (plural -lies)  Date: 1830 a periodical published four times a year