### Apatite

"A complex crystal of apatite with the faces of a third-order pyramid upon it." — Ford, 1912

### Baseball Diamond

"Base Ball is a field game played principally in the United States. It originated in the English school-boy…

### 1/3 Circle

Illustration of a circle divided into thirds. One third is shaded.

### Thomas Jefferson

Thomas Jefferson (April 13, 1743 – July 4, 1826) was the third President of the United States (1801–1809),…

### Third Kind of Lever

"In the third order of lever the power acts between the prop and the resistance, where also P : W ::…

### The Mullet

The heraldic charge borne by the third eldest son in a family.

### Fraction Pie Divided into Thirds

A circle divided into thirds.

### Fraction Pie Divided into Thirds

A circle divided into thirds with one third separated.

### One Third of a Fraction Pie

One third of a circle.

### One Third of a Fraction Pie

One third of a circle.

### One Third of a Fraction Pie

One third of a circle.

### Two Thirds of a Fraction Pie

Two thirds of a circle.

### Two Thirds of a Fraction Pie

Two thirds of a circle.

### Two Thirds of a Fraction Pie

Two thirds of a circle.

### Two Thirds and Two Sixths of a Pie Fraction

A circle subdivided into two thirds and two sixths.

### 1/3 Square

Illustration of a square divided into thirds. One third is shaded.

### Third Class Lever

A lever of the third class

### Third class lever

"A lever is an inflexible bar freely movable about a fixed axis called the fulcrum. If the power is…

### Third-class Lever

"In the third and last kind of lever, the weight is placed at one end, the fulcrum at the other end…

### Third Class Lever

"Third class lever." -Comstock 1850

### Third Class Lever

"A Lever of the Third Kind is one in which the power is between the weight and the fulcrum." —Quackenbos…

### Three Triangles Used to Compare Sides

Illustration showing three triangles. This is used to show the following theorem: If two triangles have…

### Yard And Foot

Illustration showing that one foot is one third of a yard.