Origins
The word 'erect' entered English in the late fourteenth century from Latin 'ērēctus,' the past participle of 'ērigere,' meaning 'to set up,' 'to raise,' or 'to build.' The Latin verb combines 'ē-' (a variant of 'ex-,' meaning 'out' or 'up') with 'regere' (to guide, to make straight), from PIE *h₃reǵ- (to move in a straight line). To erect something is literally to guide it upward into a straight position.
The word functions as both adjective and verb. As an adjective, 'erect' means 'upright' or 'rigidly vertical': 'standing erect,' 'with head erect,' 'an erect posture.' As a verb, it means 'to construct' or 'to raise': 'erect a building,' 'erect a monument,' 'erect a barrier.' The construction sense is actually a natural extension of the physical sense: to erect a building is to raise it from the ground into an upright position.
The relationship between 'erect' and its siblings in the *h₃reǵ- family illuminates the root's semantic range. 'Correct' means 'made thoroughly straight' (com- + regere). 'Direct' means 'made straight toward' (dis- + regere, though the prefix has been reanalyzed). 'Erect' means 'made straight upward' (ē- + regere). Each word applies the concept of straightness in a different direction: correction straightens what is crooked, direction straightens toward a target, and erection straightens upward.
Literary History
The noun 'erection' has been in English since the fifteenth century, with both architectural and anatomical senses attested from early on. The architectural sense (the act of building or raising a structure) was the primary meaning in technical and formal writing for centuries. The anatomical sense, though also present since the fifteenth century in medical texts, became the dominant popular association in the twentieth century, to the point where the architectural usage sometimes causes unintended humor.
The word 'resurrection' — one of Christianity's central theological terms — contains the same root. Latin 'resurgere' (to rise again) comes from 're-' (again) + 'surgere' (to rise), and 'surgere' itself comes from 'sub-' (from below) + 'regere' (to straighten, to direct upward). A resurrection is literally 'a straightening up again from below' — a rising from a horizontal position (death, lying in the grave) to a vertical one (life, standing erect). The connection between vertical posture and vitality runs deep in Indo-European culture and language.
The Latin adjective 'rēctus' (straight, upright), the direct past participle of 'regere,' appears in 'rectitude' (moral straightness), 'rector' (one who guides straight — a leader or head), 'rectum' (the straight part of the intestine), and 'rectangle' (a shape with straight/right angles). The recurring equation of straightness with correctness, goodness, and authority is not merely a linguistic coincidence but reflects a deep cognitive metaphor: upright is good, crooked is bad, straight is true, bent is false.