Mortise and tenons are probably used more than any other joints in woodworking.
Practical Woodworking March 18 1990, Number 2 See
mortise, mortice (mor'tis), n. [F. mortaise, fr. OF. mor'tise, n1 Ar murtazz fastened, fixed in.]
In woodworking, a cavity, hole, or recess, usually rectangular in shape, cut in the surface of a piece of timber, etc., to receive a tenon. Also in extended use.
The information above adapted from Oxford English Dictionary (online ed.) and Webster's New International Dictionary, 2d edtion. 1952.
When the mortise-and-tenon joint, the stiles-and-rails frame, and the panel set in a dado groove in the stiles and rails frame are introduced into woodworking practice, one of the one of the great revolutions in craft working begins.
The oldest, strongest joint in woodworking, among cabinetmakers and other woodworkers without doubt, it is considered the most appropriate method of joining two pieces of wood together crossways. All mortise and tenon joints consist of two parts, the "tenon," which is a rectangular projection on the end of one member, and the "mortise," which is a rectangular hole chiseled on the edge or side of the other member, and into which the tenon is fitted. The mortise and tenon joint is made with many variations, some of the most important being the blind, the through, the haunched, the keyed, and the slip joint. (Some types are exhibited in the images below on the left.)
The quote from Caroline Alexander's article in the box below -- on Stonehenge, a stone monument in Great Britain estimated to be 4,500 years old -- shows that, as a concept, the mortise and tenon joint traces far back into our history.
... Stonehenge appears as a cluster of insignificant protrusions on the big, otherwise featureless plain; and yet, even from this profane and glancing vantage, the great-shouldered silhouette is so unmistakably prehistoric that the effect is momentarily of a time warp cracking onto a lost world. Up close, amid the confusion of broken and standing stones, it still seems smaller than its reputation, notwithstanding the obvious feat represented by the erection of the famous sarsen stones; the largest weighs as much as 50 tons. Unique today, Stonehenge was probably also unique in its own time, some 4,500 years ago - a stone monument modeled on timber precedents. Indeed, its massive lintels are bound to their uprights by mortise-and-tenon joints taken straight from carpentry, an eloquent indication of just how radically new this hybrid monument must have been. It is this newness, this assured awareness that nothing like it had existed before, this revelatory quality, that is still palpable in its ruined stones. The people who built Stonehenge had discovered something hitherto unknown, hit upon some truth, turned a corner-there is no doubt that the purposefully placed stones are fraught with meaning... .
Source: Caroline Alexander, "If the Stones Could Speak: Searching for the Meaning of Stonehenge", National Geographic 213 No 6 June 2008, page 36
On the left are two images, the top one from the classic single-volume dictionary, Webster's New International Dictionary, 2nd edition and the bottom one from a 1940s industrial arts textbook for students in high school woodworking classes:
?1440 Promptorium Parvulorum ca 1440, page 344
Morteys of a tenowne, gumphus.
?c1475 Catholicon Anglicum: an English-Latin wordbook ca 1475–1483 f. 82v,
A mortase, castratura, ligium.
1546 Bishop Stephen Gardiner, A declaration of such true articles as G. Joye hath gone about to confute as false · 1546, page 35b
That were euen as wysely done of vs, as if a man wolde frame a tenaunte without a mortesse.
1592 Robert Greene, A quip for an vpstart courtier · 1st edition, 1592, Signature F3,
The ioyner though an honest man, yet he maketh his ioynts weake, and putteth in sappe in the morteses.
1656 Thomas Blount, Glossographia Anglicana Nova: Or, A Dictionary, Interpreting Such Hard Words of Whatever Language, as are at Present Used in the English Tongue, with Their Etymologies, Definition, &c. Also the Terms of Divinity, Law, Physick, Mathematicks, History, Agriculture, Logick, Metaphysicks, Grammar, Poetry, Musick, Heraldry, Architecture, Painting, War, and All Other Arts and Sciences are Herein Explain'd London: D. Brown, 1656 .
Note: Among early dictionaries of English words, Blount's is the first to give sources for definitions -- but only in a small number of cases -- and to add etymologies. In the image below is Blount's definition of "mortise and tenon"
1753 F. Price British Carpenter, page 8
Double, or pully mortices, (as they are call'd).
1823 Peter Nicholson, The Mechanic's companion: or, the elements and practice of carpentry, joinery, bricklaying, masonry, slating, plastering, painting, smithing, and turning, comprehending the latest improvements and containing a full description of the tools belonging to each branch of business; with copious ... London: James Locker, 1832, page 119;
Girders..are made with mortises, in order to receive the tenons at the end of the binding-joists.
1847 A C SMEATON Builder's Pocket Manual, page 84, and figs 29-231;
The carpenter usually connects his timbers either by notching, or by mortice and tenon. Dovetail joints are sometimes used in carpentry, but they ought not ever to be adopted, for they will always draw when the timber shrinks, and the oblique surface of the dovetail tends to force the timbers apart, acting as though it were a wedge..