English speakers use cross for a geometric mark, a monument, a hybrid animal, a peevish temper, and the central emblem of Christianity. The origin of the word cross is not a single native Old English inheritance. The form that won out is a northern borrowing that reached English through more than one neighboring language, all of them tracing, at some distance, to Latin crux.
What the word covers today
As a noun, cross can name two bars that meet at right angles, the Roman execution frame, a crucifix or churchyard monument, the sign made with the hand, or a hardship that has to be borne. Biology uses it for a hybrid; boxing for a punch thrown over an opponent’s lead; association football for a pass driven in from the flank. The verb ranges from making that hand-sign, to going from one side of a street to the other, to thwarting someone, to breeding two kinds together. The adjective, from the idea of something lying athwart, came to mean contrary and then simply ill-tempered.
Those later senses grew inside English. The earliest ones were religious, then spatial.
A northern form that outlasted its rivals
Late Old English already had cros, recorded from about the mid tenth century for the instrument of Christ’s crucifixion and as a Christian symbol. In the oldest English documents the word is sparse. It shows up especially in place-names of the north and east, including compounds of the Crosby and Crosthwaite type, and in a few late forms associated with the Peterborough area, preserved in twelfth-century manuscripts.
Most modern dictionaries treat this cros as a borrowing, probably from Old Norse kross. Norse speakers, in turn, appear to have taken the word from Old Irish cros, itself from Latin crux (oblique stem cruc-). That Hiberno-Norse path is the line given as probable in several standard desk dictionaries. A major historical dictionary is more cautious and lists several inputs at once: early Scandinavian, French, and later conversion from the English verb and adjective. A specialist survey of Scandinavian loans in English has argued that a single Hiberno-Norse source is the simplest account, and that it fits the northern geography of the early place-names. The disagreement is genuine. What is not in doubt is that English did not invent the form.
The native word for the same object was Old English rōd, which survives as rood. Cross did not grow out of rood. It replaced it in ordinary speech while rood stayed in a narrower, often ecclesiastical, register.
Middle English then ran several lookalikes side by side. Around 1200 a type cruche or crouche arrived from Medieval Latin, with a palatal consonant closer to Italian croce. After the Norman Conquest, southern writers commonly used crois and croice, from Old French croiz. That French type was frequent in the south through the early Middle English period and then faded in the fifteenth century. The northern cros, crosse, and cross remained and became the standard English word. A later Scandinavian shape kors left a dialect trail as corse or cors in Scotland and Northumbria, still visible in names such as Corstorphine.
Latin crux, and a root that may not be Indo-European
Latin crux first named a wooden stake or frame used for execution. Figuratively it already meant torture, trouble, misery. From that noun come Italian croce, French croix, Spanish and Portuguese cruz, and, by later borrowing into other Germanic languages, Dutch kruis and German Kreuz. English doublets from the same Latin stock include learned crux, the older crouch in the sense of a cross, and a family of related words such as crucial, crucify, and excruciating. Celtic relatives of the Irish form include Irish crois and Welsh croes. Scandinavian languages still show kross in Icelandic and kors in Danish and Swedish.
Where Latin got crux is uncertain. Older handbooks sometimes linked it to a root meaning to turn or bend, or to Celtic and Germanic words for a heap, a hill, or a backbone. Those comparisons have not worn well. The sounds do not line up cleanly, the meanings are not obviously the same, and the root shape does not look typically Indo-European. The word may be a loan into Latin from a neighboring or substrate language. That gap belongs in the history; a tidy prehistoric pedigree should not be invented to fill it.
How the senses fanned out
By about 1200 English cross could mean an ornamental likeness and the sign made with the right hand. In the same period it took on the Christian figurative sense of a burden borne for Christ’s sake, drawing on Gospel language about taking up a cross. A surname Cross is attested from the late twelfth century.
The mid fourteenth century adds the small figure with a body attached — a crucifix — and, by the late fourteenth, outdoor monuments in that shape. Only then does the purely geometric reading become clear: two lines meeting at right angles, without religious meaning. The theological use for Christ’s death as a necessary part of his mission is also late fourteenth century.
The verb starts near 1200 with making the sign. Going across a space is about 1400; cancelling by drawing a line through is mid fifteenth century; lying across or intersecting is late fourteenth; thwarting someone is mid sixteenth. The adjective meaning lying athwart is sixteenth century; adverse or contrary follows; of persons, peevish, from the early seventeenth, probably by way of contrary winds and ships sailing athwart. Hybrid breeding is an eighteenth-century technical extension of the spatial idea of mixing two kinds. A cheat or a fixed contest appears in the nineteenth century. A boxing blow named from the motion of the arm over an opponent’s lead is early twentieth.
None of those later uses required a new root. Speakers kept stretching the same short noun and its verb: first a Christian object, then any intersecting shape, then any act of going over, mixing, or standing in the way.
A survivor from the north
The sharpest fact in the history is geographic. Southern Middle English had a perfectly serviceable French form, crois, and the language already possessed rood. What speakers kept was the northern cros, the shape that looks closest to Old Norse kross and Old Irish cros. French croix and German Kreuz are cousins through Latin, not parents of the English word. The English form is the one that arrived by the Irish Sea and the Danelaw and then, unusually, became the national standard.