Ripping
Ripping is the process of splitting or cutting a piece of stock lengthwise with the grain. Example - taking a 2"X4"X8' and ripping it into two 1"X4"X8' pieces or 2"X2"X8' pieces. Saw blades that rip wood tend to have fewer teeth then blades that crosscut. This cut is best performed on a band saw, the long rotating blade cools rapidly and will not burn the wood like a table saw might. Feather boards are needed when working with larger pieces of stock

Crosscut
Crosscutting is the act of cutting wood across the grain. It is typically done on the table saw or miter/chop saw. Crosscutting blades have many small teeth; this produces a smooth clean cut without chip out.

Joinery
When I refer to joinery I am referring to the act of taking two pieces of wood and connecting them. Common types of joinery are mortise and tenon, plate joining (biscuits), and dovetail. Dovetail joints are the strongest and the most difficult to make. Dovetail joints have been traced back to ancient Egyptian furniture.

Mortise
A mortise is a hollow channel that a tenon sits in. the simplest real world example I can think of is a bowling ball. The three finger holes in the ball are like mortises for your fingers. In furniture building mortises are used to support the weight of the piece and strengthen the piece. Mortises are used to hold panels in doors and cabinets, by cutting a groove on all four sides of the door the panel has a place to sit in. Doors also use mortise and tenon joinery the tenon from the rail sits in the mortise of the stile on the top of the door.

Tenon
A tenon is a connecting piece of wood shaped to fit in a mortise. Fixed tenons are cut from the wood and are a single unit. Loose tenons are a shaped piece of wood that sits in two mortises. With a router loose tenon and mortise joints are easier to make, but the fixed tenon joint is stronger.

Rail and Stile
Rail - The horizontal members of a door. Stile - The vertical members of a door.