trinity

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A group consisting of three closely related members. Also called triunity.
2. n. Theology In most Christian faiths, the union of three divine persons, the Father, Son, and Holy Spirit, in one God. Also called Trine.
3. n. Trinity Sunday.

Century Dictionary and Cyclopedia

1. n. The condition of being three; threeness.
2. n. A set or group of three; a triad; a trio; a trine.
3. n. [capitalized] The union of three persons—Father, Son, and Holy Spirit—in one Godhead; the threefold personality of the one divine being. The statements of the doctrine of the Trinity in the creeds of Christendom are the result of attempts to reconcile the accepted teaching of Scripture
4. n. A symbolical representation of the mystery of the Trinity, frequent in Christian art. One of the most general forms in which the Trinity has been symbolized consists of a figure of the Father seated on a throne, the head surrounded with a triangular nimbus, or surmounted with a triple crown, Christ with the cross in front, and the Holy Spirit, in the form of a dove, resting on the cross. The mystic nnion of the three persons has also been symbolized by various emblems or devices in which three elements are combined into one whole, as, for instance, by the eqnilateral triangle, or a combination of the triangle, the circle, and sometimes the trefoil.
5. n. In heraldry, a bearing compounded of an orle, a pall, and four roundels, three at the angles of the orle where the bands of the pall meet it, the fourth at the intersection of the bands of the pall. This last roundel bears the word deus; the other three, the words pater, filius, and spiritus sanctus respectively; each part of the pall bears the word est; each part of the orle the words non est.

Wiktionary

1. n. A group or set of three people or things; triad; trio; trine.
2. n. The state of being three; threeness.

GNU Webster's 1913

1. n. (Christian Theol.) The union of three persons (the Father, the Son, and the Holy Ghost) in one Godhead, so that all the three are one God as to substance, but three persons as to individuality.
2. n. Any union of three in one; three units treated as one; a triad, as the Hindu trinity, or Trimurti.
3. n. Any symbol of the Trinity employed in Christian art, especially the triangle.

WordNet 3.0

1. n. three people considered as a unit
2. n. the cardinal number that is the sum of one and one and one
3. n. the union of the Father and Son and Holy Ghost in one Godhead