**Tangent** — Tan gent, a. [L. tangens, entis, p. pr.] Touching; touching at a single point; specifically (Geom.) meeting a curve or surface at a point and having at that point the same direction as the curve or surface; said of a straight line, curve, or… … The Collaborative International Dictionary of English

**Tangent plane** — Tangent Tan gent, a. [L. tangens, entis, p. pr.] Touching; touching at a single point; specifically (Geom.) meeting a curve or surface at a point and having at that point the same direction as the curve or surface; said of a straight line, curve … The Collaborative International Dictionary of English

**Tangent screw** — Tangent Tan gent, a. [L. tangens, entis, p. pr.] Touching; touching at a single point; specifically (Geom.) meeting a curve or surface at a point and having at that point the same direction as the curve or surface; said of a straight line, curve … The Collaborative International Dictionary of English

**Scale (map)** — The scale of a map is defined as the ratio of a distance on the map to the corresponding distance on the ground. If the region of the map is small enough for the curvature of the Earth to be neglected, then the scale may be taken as a constant… … Wikipedia

**Tangent lines to circles** — In Euclidean plane geometry, tangent lines to circles form the subject of several theorems, and play an important role in many geometrical constructions and proofs. Since the tangent line to a circle at a point P is perpendicular to the radius to … Wikipedia

**Right angle** — In geometry and trigonometry, a right angle is an angle of 90 degrees, corresponding to a quarter turn (that is, a quarter of a full circle). It can be defined as the angle such that twice that angle amounts to a half turn, or 180° [Lindahl, G.… … Wikipedia

**BMP-1 variants** — This is a complete list of variants and designations of the BMP 1 infantry fighting vehicle. It is sorted by country of origin. Variants Former USSRInfantry fighting vehicles* BMP (Ob yekt 764) Original main prototype of BMP 1 developed by the… … Wikipedia

**Map projection** — A medieval depiction of the Ecumene (1482, Johannes Schnitzer, engraver), constructed after the coordinates in Ptolemy s Geography and using his second map projection A map projection is any method of representing the surface of a sphere or other … Wikipedia

**Galvanometer** — D Arsonval/Weston galvanometer movement with the moving coil shown in red. A galvanometer is a type of ammeter: an instrument for detecting and measuring electric current. It is an analog electromechanical transducer that produces a rotary… … Wikipedia

**keyboard instrument** — ▪ music Introduction any musical instrument on which different notes can be sounded by pressing a series of keys, push buttons, or parallel levers. In nearly all cases in Western music the keys correspond to consecutive notes in the… … Universalium