: 11 The later definition by Cavalli-Sforza & Bodmer (1971) is currently used: Genetic polymorphism is the occurrence in the same population of two or more alleles at one locus, each with appreciable frequency, where the minimum frequency is typically taken as 1%.
The financial world splits up its calendar into four quarters, each three months long. If January to March is the first quarter, April to June is the second quarter, and so on, though a company's first quarter does not have to begin in January.
The IRS divides the general tax year into four reporting quarters of three months each. The first quarter is January, February and March. The second quarter is April, May and June. The third quarter is July, August and September. The fourth quarter is October, November and December. The fourth quarter of the general tax year ends for revenue on Dec. 31.