It is both the first fermat prime (2 2º + 1) and the first mersenne prime (2² - 1), as well as the first lucky prime. Three is the first odd prime number, and the second smallest prime. · a west arabic numeral, ultimately from indic numerals (compare devanagari ३ (3)), from a cursive form of three lines to represent the number three. 3 in words can be written as three. If you have saved 3 dollars, then you can write, “i have just saved three dollars. ” three is the cardinal number word of 3 which denotes a quantity. Learn about the number 3. See 3 § evolution of the … See the number three on a number line, five frame, ten frame, numeral, word,. Your guide to the number 3, an odd number which is prime. Learn the different ways number 3 can be represented. How to use three in a sentence. The meaning of three is a number that is one more than 2. Mathematical info, prime factorization, fun facts and numerical data for stem, education and fun.