a class of letters or speech sounds (b, c, d, f, g, h, j, k, l, m, n, p, q, r, s, t, v, w, x, y...

the difference between any two consecutive terms in an arithmetic sequence. The constant...

people with specialist skills who work for a business for short periods or on a part-time basis...

items that are bought, used and replaced

end purchaser who buys goods and services