theta

The"ta, n. Etym: [L., fr. Gr. qh a, the Greek letter th, Defn: A letter of the Greek alphabet corresponding to th in English; -- sometimes called the unlucky letter, from being used by the judges on their ballots in passing condemnation on a prisoner, it being the first letter of the Greek qa`natos, death. Theta function (Math.), one of a group of functions used in developing the properties of elliptic functions.

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