sad number unhappy number, a number that is not happy
sample term in statistics when a portion of the population is tested, and that proportion is said to be representative of the whole population
sample space a list of all the possible outcomes in probability
satisfy a solution is said to satisfy an equation if it produces a true statement. For example, x = 3 satisfies the equation x + 1 = 4
scalar a unit which has size but no direction
scale the marks on a graph or measuring instrument. For example, most rulers have a scale of 1cm or 1mm, sometimes both
scale a scale on a map tells us what ratio is used to compare distances on a map to distances in the real world. For example, a scale of 1:100 tells us for every 1cm on the map, there is 100cm, or 1m in real life
scalene triangle triangle with no equal sides and no equal angles
scatter diagram a diagram in statistics to compare two variables by placing dots to see if a relationship between those variables can be established
scientific notation also known as standard notation. A system to write any number, no matter how large or small so that they are easy to write and compare. Scientific notation is of the form a x 10where n is a positive integer if the number is more than one and n is a negative integer if the number is less then one. 4583 in scientific notation would be: 4.583 x 103  0.000732 in scientific notation would be: 7.32 x 10-4 The decimal must always go after the first number and the n is the number of places you moved that decimal to put it after the first digit.
score 20
SD see standard deviation
sec  the inverse of cos θ, sec θ = 1/cos θ
secant a line which passes through at least two points of a curve or a circle
sector the part of a circle between two radii and the circumferencesector
segment the part of a circle cut off by a chord
selling price price a service or article is sold for
semi-circle half a circle
septagon polygon with 7 sides (see also heptagon)
sequence a set of numbers in a particular order or follow a particular pattern
series the name given to the sum of numbers in a sequence (or pattern)
set a group of clearly defined and identifiable members
sexagesimal number system based on 60. Used for time and angles. On your calculator it is the ° ‘ ” button which stands for degrees, minutes and seconds
sigma Greek letter, capital sigma: Σ denoting the sum of and little sigma: σ denoting the standard deviation usually, although it can also be used to denote an unknown angle
sign the sign of a term tells us if it is positive or negative
significant figures the number of figures that are important to a number. For example, 135836 correct to 2 significant figures would be 130000
similar two shapes are similar if they are exactly the same shape, just not the same size
similarity tests for triangles if all angles of one triangle are the same as the second triangle (AAA) or equiangular. If the sides about an equal angle are in equal ratio. If all side of one triangle are in equal ratio to the sides of the other triangle
simple harmonic motion SHM, the motion of a body which oscillates. The formulas associated with SHM are x = acos(nt + α) or a = -n2x
simple interest when money is invested and interest is only earned on the original amount invested. I = PRN/100 where I is interest, P is principle invested, R is interest rate and N is the number of periods invested for
simplify to answer a question in its most simple or basic form
Simpson’s Rule

used to find approximate areas of irregular shapes  A = h/3(dF + 4dM + dL)   (for use with General course) or 

A =h/3{f(a) + f(b) + 4(sum of odd functions) + 2(sum of even functions)}  (for use with Advanced course)

simultaneous occurring at the same time
simultaneous equations two or more equations, solving them will give you the point of intersection between them
sin sin θ = opp/hyp
sketch to draw without actually plotting
skew distribution a distribution not symmetrical. The first diagram is an example of a positive skew. The ‘tail’ is being pulled in the positive direction (ie to the right). in the second diagram, the ‘tail’ is being pulled in a negative direction (ie left), so is negatively skewed
skew lines lines that are not parallel, but do not intersect
slant height the height from the vertex to the base edge of a pyramid or cone, not the perpendicular height. In this figure the slant height is represented by the letter L or s
small circle circles drawn around the earth that do not pass through the centre. All circles of latitude, except the equator are small circles
solid three dimensional shape
solid of revolution shape formed when part of a line or curve is rotated about the x or y axis. V =  π ab y2 dx if rotated about x-axis. V = π c d x2 dy if rotated about y-axis
solution another name for the answer to a problem
solve instruction to work out answer to question posed
speed how much distance is covered in a certain time period. For example, 60km/h means for every hour travelled, 60km of distance will be covered
sphere round solid shape, a ball $$V=\frac43\pi r^3$$ $$SA=4\pi r^2$$sphere
spherical shaped like a sphere
spread statistical term to measure how far from the average the data is. Measures of spread include the range, the interquartile range, the standard deviation
square four sided shape with all sides equal, opposite sides parallel, adjacent sides perpendicular. Diagonals are equal and bisect at right anglessquare
square numbers 1, 4, 9, 16, 25, 36, 49, 64, 81, 100….
square pyramid Solid shape with a square base and four triangular faces
square root to find the square root of a number we need to find a number that multiplies by itself to give us the number we want the square root of. For example 2 x 2 = 4, so the √4  = 2. 8 x 8 = 64, so the √64  = 8.
standard deviation SD measures the spread of a distribution. Essentially, the larger the standard deviation, the more spread out, the smaller the standard deviation, the less spread out, or the more consistent the scores are
stationary point the point on any curve where the tangent is parallel to the x-axis, having a gradient of zero. It is neither increasing, nor decreasing. Each stationary point must be either a maximum, minimum or a horizontal point of inflection. The stationary point can be found using dy/dx = 0 (see also turning point)
straight line that is not curved or bent
straight angle angle of 180°
subject the subject of an equation is the single letter that equals all the other terms. For example in y = 2x + 3z, y is the subject
substitution replacing a letter in a formula with a number, another letter or another expression
subtend is opposite to
sum to add up, find the total of
supplementary angles add to 180°
surd a number with a root that cannot be simplified into a rational number. √12 may be simplified to 2√3, but no further. All surds are irrational numbers
survey term in statistics when a portion of the population is tested, and that proportion is said to be representative of the whole population
symbol sign or letter used to represent something else. The symbol = represents ‘equals’. The Greek symbol θ, theta, is used to represent unknown angles.
symmetric having symmetry
symmetry if you cut a shape in half, it will be the same on both sides