The Christian Doctrine teaches the unity of Father, Son and the Holy Spirit are the three persons within one Godhead.

There are three states of matter, solid, liquid and gas.

Living things are divided into three groups based on their genetic similarity. The three groups are:

Archaea: very ancient prokaryotic microbes.

Eubacteria: More advanced prokaryotic microbes.

Eukaryota: All life forms with eukaryotic cells including plants and animals

The prehistory and history of civilization is classified into three ages the Stone Age, Bronze Age, and Iron Age.

There are three parts to Atoms, protons, neutrons and electrons.

There are three families of Quarks

Family 1 Lightest quarks (baryons and mesons (protons, neutrons etc.)

Up Down

anti-Up

anti-Down

Family 2 Heavier quarks (Higher energy physics world)

strange charm

anti-strange

anti-charm

Family 3 (Very high energy physics world) Heaviest quarks

Top Bottom or beauty

anti-Top

anti-Bottom

Einstein's Three Rules of Work: 1) Out of clutter find simplicity; 2) From discord find harmony; 3) In the middle of difficulty lies opportunity.

A writer needs three things, experience, observation, and imagination, any two of which, at times any one of which, can supply the lack of the others.--William Faulkner

There are three kinds of intelligence: one kind understands things for itself, the other appreciates what others can understand, the third understands neither for itself nor through others. This first is excellent, the second good, and the third useless.--Niccolo Machiavelli

Every scientific truth goes through three states: first, people say it conflicts with the Bible; next, they say it has been discovered before lastly, they say they always believed it.--Louis Agassiz

There are three questions which in life we have over and over again to answer: is it right or wrong? is it true or false? is it beautiful or ugly? Our education ought to help us to answer these questions.--John Lubbock

Every truth passes through three stages before it is recognized. In the first it is ridiculed; in the second it is opposed; in the third it is regarded as self-evident.--Arthur Schopenhauer

There are three reasons why lawyers are being used more and more in scientific experiments. First, every year there are more of them around. Second, lab assistants don't get attached to them. And, third, there are some things that rats just won't do.-- Unknown

There are three roads to ruin; women, gambling and technicians. The most pleasant is with women, the quickest is with gambling, but the surest is with technicians.--Georges Pompidou

The three signs of great men are -- generosity in the design, humanity in the execution, moderation in success.--Otto von Bismarck

There are three things which are real: God, human folly, and laughter. Since the first two pass our comprehension, we must do what we can with the third.--Aubrey Menen

There were three musketeers, three little pigs, three billy goats Gruff, Goldilocks and the three bears, three blind mice and three Stooges.

And the Grand Daddy of All!!!

There are three types of rocks!

Igneous, sedimentary, and metamorphic

Praise Rock!

p.s my avi has three rocks!