What is Church doctrine? The answer, as for most terms, depends on its context. As used in this site, the term Church, with a capital C, means The Church of Jesus Christ of Latter-day Saints. What is the doctrine of the Church? The scriptures brought forth by the Church’s founding prophet, Joseph Smith—the Book of Mormon, the Doctrine and Covenants, and the Pearl of Great Price—use the word doctrine repeatedly. What did that term mean in Joseph Smith’s day?
The almost universal reference source on American English word meanings in Joseph Smith’s day was Noah Webster’s 1828 American Dictionary of the English Language. Webster gives five definitions of the term doctrine.
His first definition of doctrine is “In a general sense, whatever is taught.” Under this definition, Church doctrine is whatever the Church teaches. Because the Church is based on continuing revelation, it updates its scriptures and manuals to be consistent with the latest revelation. People sometimes ask, “Does Church doctrine change?” Under this definition, the answer is, of course, yes. The latest revelation supersedes what precedes it. The words of living prophets are considered more authoritative than those of prophets from a different age.
Webster’s second definition of doctrine is “The act of teaching.” Church doctrine, in this sense, is Church education. Teachers in the Church Educational System engage in doctrine, the act of teaching.
Webster’s third definition is “Learning; knowledge.” Under this definition, doctrine in the most general sense is just knowledge. Church doctrine in this sense can mean learning or knowledge about the Church. In this sense, Church doctrine can also have a broader meaning. The purpose statement of the Church Educational System includes the language, “CES consists of a number of institutions that provide religious and secular education under the direction of priesthood leadership and the guidance of the Holy Ghost.” Church Educational System teachers, such as those at Church universities, therefore go beyond religious instruction and provide secular instruction that includes the latest scientific theories and hypotheses. Thus, Church doctrine in this broadest of senses embraces all knowledge. Is all this knowledge true? Clearly not. Just compare the science textbooks of one generation to those of the next to understand that some ideas prove wrong over time and are superseded by later discoveries.
Webster’s fourth definition is “The truths of the gospel in general.” Webster relied heavily on the Bible because it was widely taught and read in his day and culture. In defining doctrine as “the truths of the gospel in general,” Webster essentially recognizes that among all of the knowledge that is taught, some will be gospel truths. Webster defines “truth” as “Conformity to fact or reality; exact accordance with that which is, or has been, or shall be.” This is very close to the definition of truth given in Doctrine and Covenants 93:24: “And truth is knowledge of things as they are, and as they were, and as they are to come.” When using the term doctrine in this sense, we can say that Church doctrine does not change. Gospel truths (facts, realities) remain the same through time.
Finally, Webster’s entry on doctrine ends with “Instruction and confirmation in the truths of the gospel.” This definition is a mixture of definitions 2 and 4. Missionaries, for example, teach and testify of gospel truths. What they do is Church doctrine in this sense.
The Church Doctrine part of Study by Faith will focus primarily on doctrine as meant in definitions 1 and 4. In other words, it will focus on what the Church teaches and how it changes over time, with emphasis on the latest teachings since they supersede what was taught earlier. It will also seek to identify the gospel truths that do not change over time.
At the outset, Study by Faith will rely primarily on the Church’s standard works and the general conference addresses of Church leaders, two sources generally recognized by Church leaders and members as sources of Church doctrine.
 Noah Webster, An American Dictionary of the English Language, vol. 1(New York: S. Converse, 1828), s.v. “Doctrine.” Webster provides biblical examples and references for each definition.
 “Purpose of the Church Educational System,” https://www.churchofjesuschrist.org/church-education/purpose-of-ces?lang=eng
 Webster, An American Dictionary, s.v. “Truth,” def. 1.