This is by no means all inclusive. As I blog I will add terms (alphabetically) to this list that I have mentioned in a post that I believe are terms that only Mormons will know (or ones that Mormons have a slightly different definition for). I will be using my own terminology (so this may end up like a holy Urban Dictionary) so if you ever want a more official definition, please check out this page on the LDS website.
Atonement: The atonement is the act that Christ performed in the Garden of Gethsemane to offer payment for our sins. Additionally, this act brought upon Christ all of the sorrows, trials, and afflictions of all mankind. Because of this act, Christ literally knows exactly what you are going through, because he went through it himself. The atonement allows us to repent for our sins and to receive comfort.
Blessing: Receiving a blessing is like having a specific prayer offered for your wellbeing. Often individuals will receive blessings when they're sick or going through a hard time. These blessings aren't set in stone, any worthy male who holds the appropriate level of the Priesthood can give them to an individual. They offer inspired words of comfort or healing that are completely influenced by the Holy Ghost. Some blessings occur at set points in life, such as a baby blessing or a father's blessing at the start of each school year. The key is that they aren't set prayers; they are tailored to specific people in specific situations in the moment that they are given.
Book of Mormon: The Book of Mormon is much like the Bible in the respect that prophets of ancient times communicated with God and then wrote down their experiences, people's history, and revelations. The book revolves around individuals living on the American continents leading up to and after the birth of Christ. In order, the books of the Book of Mormon are: 1st Nephi, 2nd Nephi, Jacob, Enos, Jarom, Omni, Words of Mormon, Mosiah, Alma, Helaman, 3rd Nephi, 4th Nephi, Mormon, Ether, and Moroni.
Church of Jesus Christ of Latter-day Saints: This is the official name of the Mormon church. Mormon is a nickname given to the church due to the Book of Mormon. The name recognizes that first our faith is a Christ centered faith, and second that we are saints living in the latter (or last) days before Christ will return to the earth. Often this is abbreviated to LDS.
Doctrine and Covenants: The Doctrine and Covenants is a set of modern day teachings or revelations. The vast majority were received and written by Joseph Smith.
Missionary Training Center (MTC): There are multiple MTC's in the world and they all function for the same purpose; to train prospective missionaries at the outset of their mission. If an individual is learning a second language they will spend time doing that in the MTC. All missionaries study the scriptures and missionary curriculum during their training. Argentina, Brazil, Chile, Columbia, the Dominican Republic, Ghana, Guatemala, Mexico, New Zealand, Peru, the Philippines, South Africa, Spain, the UK, and Provo, Utah (my prospective MTC) all boast an MTC.
Patriarchal Blessing: A Patriarchal blessing is a personalized prayer that an individual receives from someone called a patriarch. Essentially it is a blessing that is tailored to a specific person that lists potential strengths, weaknesses, blessings, events, or goals a person may encounter in their life. Experiencing what is mentioned in a blessing is predicated on faith. They are very personal letters from God in a way. Which is why I may refer to very small or vague areas of mine, but will never quote it online or share it in its entirety.
Pearl of Great Price: The Pearl of Great Price contains further elaborations of some biblical principles as well as the Joseph Smith History, which is self-explanatory by its name.
Preach My Gospel: Preach My Gospel is a book that was published by the Church of Jesus Christ of Latter-day Saints for the use of its members. It is a manual that is used by proselyting missionaries to help them understand how to teach individuals. It can be used by anyone who is in a teaching position or who may find it valuable in their general study. You can find an online PDF of the text here.
Scriptures: When an LDS person refers to scriptures they are referencing the King James Bible, the Book of Mormon and other canonized works such as the Doctrine and Covenants or Pearl of Great Price.
The Temple: Mormons practice temple worship as people did in the Old and New Testament. As a part of temple practices, Mormons covenant to live worthy of eternal blessings and promise to strive to live an uplifting life. They also participate in what is called proxy temple work, in which they perform ordinances for individuals who are deceased who didn't have the opportunity to accept Christ's gospel while on the Earth. Here are a few good elaborations on ordinance work for the dead.