In this article, discover a comprehensive list of math words that start with the letter “O” and expand your mathematical vocabulary effortlessly.

**Octagon-**A polygon with eight sides and eight angles.**Octahedron-**A polyhedron with eight faces.**Octal-**A base-8 number system.**Ordinate-**The y-coordinate in a Cartesian coordinate system.**Origin-**The point of intersection of the axes in a coordinate system (0,0).**Odometer-**An instrument for measuring distance traveled.**Operation-**A mathematical process (e.g., addition, subtraction, multiplication, division).**Ordinal-**A number that indicates position or order.**Order of Operations-**Rules that define the sequence in which operations should be performed (PEMDAS).**Odds-**The ratio of the probability of an event occurring to the probability of it not occurring.**Orthogonal-**Perpendicular; at right angles.**Orthocenter-**The point where the altitudes of a triangle intersect.**Oblique-**Not parallel or perpendicular; slanting.**Oblong-**Having an elongated shape.**Oblate-**Flattened at the poles (shape of an ellipsoid).**Oblique Angle-**An angle that is not a right angle or a multiple of a right angle.**Open Set-**A set that does not include its boundary points.**Oscillate-**To move or swing back and forth in a regular rhythm.**Oscillation-**The act of oscillating; a regular variation in magnitude or position.**One-**to-One Correspondence – A situation where each element of one set is paired with a unique element of another set.**Outcome-**The result of a probabilistic experiment.**Outlier-**A value significantly higher or lower than most of the values in a data set.**Opposite-**In a right triangle, the side opposite the angle of interest.**Ordered Pair-**A pair of numbers (x, y) that represent a point in a coordinate system.**Optimization-**The act of making something as effective or functional as possible.**Orthographic Projection-**A method of representing three-dimensional objects in two dimensions.**Overlap-**To lie over part of something; to have parts in common.**Omega-**The last letter of the Greek alphabet, often used to denote the last or most significant in a series, or the resistance in electrical engineering.**Order-**The number of elements in a set or the degree of a polynomial.**Orientation-**The relative physical position or direction of something.**Odd Number-**An integer that is not divisible by 2.**Obverse-**The counterpart of a proposition obtained by negating both the hypothesis and the conclusion.

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