They add up to a whole of some kind, add up to 90 degrees.
Complementary
Two angles that add up to 180 degrees.
Supplementary
Having the same shape; having corresponding sides proportional and corresponding angles equal
Similar
Same size shape, measure, length etc.
Congruent
A pair of adjacent supplementary angles.
Linear pair
A transformation that produces the same shape as the original but is a different size.
Dilation
A number that scales or multiplies some quantity.
Scale Factor
Deals with the relations of sides and angles of triangles.
Trigonometry
opposite over hypotenuse
Sine
Adjacent over hypotenuse
Cosine
Opposite over adjacent.
Tangent
Corresponding in size 
Proportional
Between two similar figures is the ratio of any pair of corresponding sides.
Similarity Ratio
(of a line) intersecting a system of lines.
Transversal
(of a triangle) having two sides of equal length.
Isosceles
having all of its sides of the same length in a triangle.
Equilateral
the longest side of a right triangle, it is opposite of the right angle.
Hypotenuse
It meets or crosses at right angles.
Perpendicular
It cuts an object into two equal parts, is applied to angles and line segments.
Bisector
A point on a line segment that divides it into two equal parts,the halfway point of a line segment
Midpoint
A quadrilateral with both pairs of opposite sides parallel. 
Parallelogram