BONUS (a jocular application of the Lat. bonus, for bonum, "a good thing"), a sum paid to shareholders in a joint-stock company, as an addition to the ordinary dividend, and generally given out of accumulated profits, or out of profits gained from exceptional transactions. As used by insurance companies, the word denotes the addition made to the amount of a policy by a distribution pro rata of accumulated profits or surplus. In a more general sense, bonus is any payment or remuneration over and above what is due and promised.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)