Prefixes of Quantity
This is a great list to memorize! These prefixes are like "number codes" hidden inside English words. Once you know them, you can guess the structure of objects, timeframes, and even animals.
Here are some common examples for each:
| Prefix | Meaning | Examples |
|---|---|---|
| Uni- | One | Unicycle (one wheel), Uniform (one shape/style), Unique (only one of its kind) |
| Bi- | Two | Bicycle (two wheels), Bilingual (speaking two languages), Biweekly (every two weeks) |
| Tri- | Three | Triangle (three angles), Tricycle (three wheels), Triple (three times as much) |
| Quadr- | Four | Quadrilateral (four sides), Quadruplets (four babies), Quadrant (one of four parts) |
| Penta- | Five | Pentagon (five sides), Pentathlon (a contest with five events) |
| Hexa- | Six | Hexagon (six sides), Hexagram (a six-pointed star) |
| Hepta- | Seven | Heptagon (seven sides), Heptathlon (a contest with seven events) |
| Oct- | Eight | Octopus (eight legs), Octagon (eight sides), October (originally the 8th month) |
| Novem- | Nine | November (originally the 9th month), Nonagon (a nine-sided shape) |
| Deca- | Ten | Decade (ten years), Decathlon (ten events), Decimal (based on ten) |
| Poly- | Many | Polygon (many sides), Polyglot (someone who speaks many languages) |
| Omni- | All | Omniscient (all-knowing), Omnivore (eats all things—plants and meat) |
Visualizing the Geometry
In your Word Roots book, you will often see these used to describe shapes. Seeing how the "prefix + -gon (side)" pattern works makes it much easier to remember.
A Quick Tip for "Oct-" and "Dec-"
You might notice that October is the 10th month and December is the 12th, even though their roots mean 8 and 10. This is because the Roman calendar originally started in March! When January and February were added later, the names "stuck" even though the positions shifted.
Applying it to your Life
Think of your Usui Reiki practice; you might consider it a uni-focused practice when you are doing self-healing, as you are concentrating on "one" energy system (your own) to avoid the "cold" energy of others.
Would you like me to create a quick "fill-in-the-blank" quiz using these prefixes to see how many you can spot?
can you explane to me why October mean tenth month, and so on november, december
It feels like a mistake, doesn't it? If Oct- means eight, then October should be the eighth month! You are 100% correct about the linguistic roots, but history (and a couple of Roman emperors) changed the timing.
The Original Roman Calendar
In the earliest Roman calendar, there were only 10 months. The year started in March, because that was the beginning of spring and the time for military campaigns to begin.
If you count starting from March, the math works perfectly:
| Position | Month | Root Meaning |
|---|---|---|
| 7th | September | Septem (Seven) |
| 8th | October | Octo (Eight) |
| 9th | November | Novem (Nine) |
| 10th | December | Decem (Ten) |
What Changed?
The Romans eventually realized that a 10-month calendar (about 304 days) didn't match the solar year. The "winter" period was just a nameless gap of time that didn't belong to any month.
- Adding January and February: To fix the calendar, King Numa Pompilius added January and February to the beginning of the year.
- The Shift: When these two months were pushed to the front, every other month got "pushed" two spots back.
- October (the 8th month) was pushed into the 10th spot.
- November (the 9th month) was pushed into the 11th spot.
- December (the 10th month) was pushed into the 12th spot.
Why didn't they change the names?
By the time the calendar was fixed, people were already used to the names. Even though the "math" was now wrong, the names stuck. It’s a bit like how we still say we "dial" a phone number even though we use touchscreens—the language stays even when the technology or system changes.
Since you are studying quantity prefixes, have you noticed any other words where the "number" in the word doesn't quite match how we use it today?