| Abbreviation | Definition |
|---|---|
| OCT | Optimized Cardioid Triangle |
| OCTM | Ohio Coucil of Teachers of Mathematics |
| OCTM | Ohio Council for Teachers of Mathematics |
| OCTM | Ohio Council of Teachers of Mathematics |
| OCTM | Oklahoma Council of Teachers of Mathematics |
| OCTM | Oregon Council of Teachers of Mathematics |
| OD | Off Diagonal |
| ODE | Ordinary Difference Equation |
| ODE | Ordinary Differential Equation |
| ODS | Operating Deflection Shape |
| OECV | Overall Error Coefficient of Variation |
| OEIS | Online Encyclopedia of Integer Sequence |
| OEMS | Oklahoma Elementary Mathematics Specialist |
| OF | Ordered Field |
| OFDM | Orthogonal Frequency Division Multiplexing |
| OG | Observational Game |
| OG | Optimal Guess |
| OGSM | Organization of Graduate Students in Mathematics |
| OHP | Outer Helmholtz Plane |
| OIV | Optimistic Initial Value |