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Charles Buck Theological Dictionary [1]

A person not conforming to any particular opinion or standard, but of such moderation as to suppose that people will be admitted into heaven, although of different persuasions. The term was more especially applied to those pacific doctors in the seventeenth century, who offered themselves as mediators between the more violent Episcopalians, and the rigid Presbyterians and Independents, respecting the forms of church government, public worship, and certain religious tenets, more especially those that were debated between the Arminians and Calvinists. The chief leaders of these Latitudinarians were Hales and Chillingworth; but More, Cudworth, Gale, Witchcot, and Tillotson, were also among the number. These men, although firmly attached to the church of England, did not go so far as to look upon it as of divine institution; and hence they maintained, that those who followed other forms of government and worship, were not on that account to be excluded from their communion.

As to the doctrinal part of religion, they took the system of Episcopius for their model, and, like him, reduced the fundamental doctrines of Christianity to a few points; and by this manner of proceeding they endeavoured to show the contending parties, that they had no reason to oppose each other with such animosity and bitterness, since the subjects of their debates were matters of an indifferent nature with respect to salvation. They met, however, with opposition for their pains, and were branded as Atheists and Deists by some, and as Socinians by others; but upon the restoration of Charles II. they were raised to the first dignities of the church, and were held in considerable esteem.

See Burnet's History of his own Times, vol. 1: b. 11. p. 188; Mosheim's Ecc. Hist. vol. 2: p. 501. quarto edit.

Webster's Dictionary [2]

(1): ( a.) Not restrained; not confined by precise limits.

(2): ( a.) Indifferent to a strict application of any standard of belief or opinion; hence, deviating more or less widely from such standard; lax in doctrine; as, latitudinarian divines; latitudinarian theology.

(3): ( n.) A member of the Church of England, in the time of Charles II., who adopted more liberal notions in respect to the authority, government, and doctrines of the church than generally prevailed.

(4): ( n.) One who is moderate in his notions, or not restrained by precise settled limits in opinion; one who indulges freedom in thinking.

(5): ( n.) One who departs in opinion from the strict principles of orthodoxy.

(6): ( a.) Lax in moral or religious principles.