Cone—a solid with a circular bottom that rises steadily to a point.  A common example is an ice cream cone.

Conjecture—an educated guess based on what you already know about a situation

Formula—mathematical expression which calculates area, volume, perimeter, etc.

Right circular cylinder—a solid which has a parallel circular top and bottom and has a height.  A common example is a soup can.  It is commonly called a cylinder.

Sphere—a solid formed from all the points equidistant to a given point.  A common example is a ball.

Spreadsheet:  a collection of rows and columns containing both text and numeric information—formulas allow for calculation based on information contained in individual cells 

Volume—amount of space inside a solid.  It is calculated using a formula.