**sample 样本**

A set of data or elements drawn from a larger population and analyzed to estimate the characteristics of that population.

**scale 规模，尺度，比例，比例尺，天平**

- A proportion used in determining the dimensional relationship of a representation to that which it represents: a world map with a scale of 1:4,560,000.
- A system of notation in which the values of numerical expressions are determined by their places relative to the chosen base of the system.
- A balance or any of various other instruments or devices for weighing

**scale drawing 缩尺图**

**scalene triangle 不等边三角形**

A triangle whose sides are all of different lengths.

**scatter plot, scatter graph, scatter chart, scattergram, scatter diagram 散点图**

A type of plot or mathematical diagram using Cartesian coordinates to display values for typically two variables for a set of data.

**scientific notation 科学记数法**

A way of expressing numbers that are too big or too small to be conveniently written in decimal form, multiplied by 10 to the appropriate power, as 1385.62 written as 1.386 × 10^{3}.

**seasons 季度**

One of the four natural divisions of the year, spring, summer, autumn, and winter, beginning astronomically at an equinox or solstice, but geographically at different dates in different climates.

**secant 正割；割线**

- A straight line intersecting a curve.
- A trigonometric function that in a right-angled triangle is the ratio of the length of the hypotenuse to that of the adjacent side; the reciprocal of cosine.

**second 秒，第二**

- A unit of time that is equal to 1/60th of a minute.
- The ordinal number assigned to item number two in a series

**second hand 秒针**

The hand that indicates the seconds on a clock or watch.

**section 部分, 剖面图**

- Any of the parts into which sth is divided.
- A drawing or diagram of sth as it would look if it were cut from top to bottom or from one side to the other.

**sector 扇形, 磁区**

- The portion of a circle bounded by two radii and the included arc.
- A measuring instrument consisting of two graduated arms hinged together at one end.
- A portion of a storage device in computer that making up the smallest addressable unit of information.

**sector graph 扇形图；圆形分格统计图表**

A graph is presented which shows the expenditures, revenue, and fiscal or some other informations. The data would be presented by divide a circle into several sectors, and usually in percentages, which are amounts that are part of a whole – the most used percentage amount is out of 100.

**segment 线段, 弓形**

- The portion of a line between any two points on the line. Also called line segment.
- The portion of a sphere cut off by two parallel planes.
- The area bounded by a chord and the arc of a curve subtended by the chord.

**semi-major axis 长半轴**

One-half the major axis of an ellipse; the distance from the center of an ellipse to one end. The major axis is the longer or longest axis of an ellipse or ellipsoid.

**semi-minor axis 短半轴**

One-half the minor axis of an ellipse. The minor axis is the axis of an ellipse that is perpendicular to the major axis at a point equidistant from the foci.

**semicircle / semicircumference 半圆**

One half of a circle.

**sentence 句子**

A grammatical unit of one or more words that expresses an independent statement, question, request, command, exclamation, etc, usually containing a subject and a verb.

**sequence 数列**

an ordered set of numbers or other mathematical entities in one-to-one correspondence with the set of positive integers.

**set 集合**

A collection of distinct elements having specific common properties.

- {a, e, i, o, u} is the set consisting of the vowels of the alphabet.
- {1, 2, 3, … 100} is the set of the first 100 positive integers.
- The set of all real numbers that are greater than 1 can be written as either {x | x∈R and x>1} or {x : x∈R and x>1}.

**shape 形状**

A geometric form, e.g. a square, triangle, cone, or cube.

**side 边, 侧面**

- Any line segment forming part of the perimeter of a plane geometric figure.
- One of the flat surfaces of sth that is not the top or bottom, front or back.

**side view 侧面图**

A view of sth from the side.

**sign 符号**

A symbol indicating an operation.

+, -, ×, ÷, =, >, <, { }, //, ⊥, ≌, ⊙, Rt△, Ø, U, ∩

**similar 相似**

Having corresponding angles equal and all corresponding sides in the same ratio.

**sine 正弦**

- In a right triangle, the ratio of the length of the side opposite an acute angle to the length of the hypotenuse.
- A trigonometric function equal to the ratio of the ordinate of the end point of the arc to the radius vector of this end point, the origin being at the center of the circle on which the arc lies and the initial point of the arc being on the x-axis. Abbreviation: sin.

**size 大小，尺寸**

The physical dimensions, proportions, magnitude, or extent of an object.

**skip counting 跳跃计数**

A mathematics technique taught as a kind of multiplication in reform mathematics textbooks such as TERC. In older textbooks, this technique is called counting by twos (threes, fours, etc.). In skip counting by twos, a person can count to 10 by only naming every other number: 2, 4, 6, 8, 10. Combining the base (two, in this example) with the number of groups (five, in this example) produces the standard multiplication equation: two multiplied by five equals ten.

**slide 滑动**

To move along in continuous contact with a smooth or slippery surface.

**slope 坡度，斜率**

- The tangent of the angle between a given straight line and the x-axis of a system of Cartesian coordinates.
- The derivative of the function whose graph is a given curve evaluated at a designated point.

**solid 固体, 立体图形**

- A substance that resists change in shape, unlike a liquid or gas.
- A three-dimensional (a three-dimensional geometric figure or object) geometric figure or object.

**solstice 冬至；夏至**

Either of the two times of the year at which the sun reaches its highest or lowest point in the sky at midday, marked by the longest and shortest days. When the sun is at its greatest distance from the celestial equator: about June 21, when the sun reaches its northernmost point on the celestial sphere, or about December 22, when it reaches its southernmost point.

**sort 数组元素的排序**

To arrange things in a set order, especially automatically, as some computer programs do with data.

**space 空间**

A collection of points that have geometric properties in that they obey set rules , e.g. a Euclidean space that is governed by Euclidean geometry.

**speed 速度**

The rate at which sb/sth moves or travels. Galileo defined speed as the distance covered per unit of time. In equation form, this is v = d/t.

Instantaneous speed: Speed at some instant, or assumed constant during a very short period of time.

**sphere 球面, 球体**

A solid figure that is completely round, with every point on its surface at an equal distance from the centre.

x^{2} + y^{2} + z^{2} = r^{2}

**spiral 螺旋，盘绕**

- A curve on a plane that winds around a fixed center point at a continuously increasing or decreasing distance from the point.
- A three-dimensional curve that turns around an axis at a constant or continuously varying distance while moving parallel to the axis.

**spring balance 弹簧秤**

A device in which an object to be weighed is attached to the end of a helical spring, the extension of which indicates the weight of the object on a calibrated scale.

**square 正方形；平方**

- A polygon having four equal sides and four equal angles.
- The product obtained when a number or quantity is multiplied by itself: 49 is the square of 7.
- Used after a number to give a measurement of area.

**square centimeter 平方厘米**

**square kilometer 平方千米**

**square measure 平方面积制**

**square meter 平方米**

**square number 平方数**

**square root 平方根**

A number or quantity that when multiplied by itself gives a given number or quantity. The quantities +6 and −6 are square roots of 36 since (+6)×(+6)=36 and (−6)×(−6)=36.

**standard form 标准符号法；标准型**

A canonical, normal, or standard form of a mathematical object is a standard way of presenting that object as a mathematical expression. The distinction between “canonical” and “normal” forms varies by subfield.

**standard normal distribution 标准正态分布**

Statistics a normal distribution with mean 0 and variance 1。

**standard notation 标准记数法**

General agreements in the way things are written or denoted. The term is generally used in technical and scientific areas of study like mathematics, physics, chemistry and biology, but can also be seen in areas like business, economics and music.

**statistics 统计**

A branch of mathematics dealing with the collection, analysis, interpretation, and presentation of masses of numerical data.

**stem and leaf plot / stemplot 干茎叶图**

A histogram-like instrument for presenting quantitative data in a graphic format, which helps visualise its distribution. The data plot presents part of the data value as the stem and the rest of the data value—the leaf—to form groups or classes; the stem and leaf plot is useful for quickly sorting data.

**straight angle 平角**

An angle of 180°.

**straight line 直线**

A line traced by a point traveling in a constant direction; a line of zero curvature.

**substitution 代入**

The replacement of a term of an equation by another that is known to have the same value in order to simplify the equation.

**subtended angle 包角，对向角**

An angle subtended by an arc, line segment, or other curve is one whose two rays pass through the endpoints of the arc.

**subtract 减**

To take a number or an amount away from another number or amount.

**subtraction 减法**

It is signified by the minus sign: −

**subtrahend 被减数**

A quantity or number to be subtracted from another. In “5 – 2 = 3”, the subtrahend is 5.

**successive 连续**

Following in an uninterrupted sequence.

**sum 和, 金额**

- An amount obtained as a result of adding numbers.
- An amount of money.

**summary statistics 统计摘要**

Summarize a set of observations, in order to communicate the largest amount of information as simply as possible.

**supplementary angles 补角**

Two angles whose sum is 180°.

**surd 无理数，无理数的**

Not capable of being expressed in rational numbers, such as √2.

**surface 表面**

- The boundary of a three-dimensional figure.
- The two-dimensional locus of points located in three-dimensional space.

**surface area 表面积**

The extent of a 2-dimensional surface enclosed within a boundary.

**survey 测量**

To determine the boundaries, area, or elevations of (land or structures on the earth’s surface) by means of measuring angles and distances, using the techniques of geometry and trigonometry.

**symbol 符号**

A sign, number, letter, etc. that has a fixed meaning, especially in science, mathematics and music.

**symmetry 对称，相似**

- The correspondence of the form and arrangement of elements or parts on opposite sides of a dividing line or plane or about a center or an axis.
- A relationship in which there is correspondence or similarity between entities or parts.