The Number 3: Properties and Meanings

3 is a Prime Number.

3 is a Lucas Number.

3 is a Mersenne Number.

3 is a Triangular Number.

3 is a Fibonacci Number.

3 is a Cullen Number.

3 is the 1st Delannoy Number.

3 is a Super Catalan Number.

3 can be Partitioned in 3 ways.

The 3 Monoclinic crystal classes.

The 3 Orthorhombic crystal classes.

The Chemical Element Lithium has an atomic number of 3.

The Chemical Element Helium has one Stable Isotope. It has 3 neutrons.

The 3 gunas: three qualities, known as Gunas, that exist together in equilibrium: Sattva (purity); Rajas (activity, passion, the process of change); and Tamas (darkness, inertia).

The 3 primary colours: red, green and blue.

In Christianity there are three theological Virtues: faith, hope and charity.

Vices: In Buddhism: the three roots of evil namely greed, hatred and delusion. I have a public domain ebook in my library section which explores these roots:
The Roots of Good and Evil: An Anthology by Nyanaponika Thera

The physical world has 3 dimensions.

The 3 Mother Letters of the Hebrew alphabet: Aleph, Mem and Shin.

Yin, Yang and Tao.

Film: Three Men and a Baby.

Film: 3 Ninjas.

Film: Close Encounters of the Third Kind.

Film: 3-Way.

The Year 3 AD

Servius Sulpicius Galba, roman emperor was born in the year 3 AD

In the year 3 AD Sadiq Hidajat, Persian writer (Blind Person Owl), was born.