Θ

Symbol

 * 1)  Θ, the ordinal number with the same cardinality as the smallest set larger than the real numbers; the smallest nonzero ordinal number such that there exists no surjection onto it from the real numbers.
 * 2)  A pentaquark.
 * 3)  Protruded tongue.

Etymology
From.

Letter

 * 1) The letter theta, the eighth letter of the ancient Greek alphabet.

Letter

 * 1) The upper case letter theta (θήτα), the eighth letter of the modern Greek alphabet.

Numeral

 * 1) The number nine in Greek numerals.