What is the difference between a concourse and a pier?
In terminal designs, the main difference between a pier and a concourse is that a pier is connected by terminal buildings on one side, but a concourse has separate terminal buildings connected by transportation either under or over ground.

In practice, the terms "terminal" and "concourse" are often used interchangeably, with "satellite" being used in that specific case, and "piers" being referred to as terminals or concourses.

Simple

Small terminal with a few gates.

Linear

Longer than a simple terminal, with gates on one side. May be curved or straight.

Concourses

Standard terminal with gates on one side, with additional linear terminals connected underground or by buses (occasionally by a bridge), each with gates all around. Each is generally designated as a different concourse.

Standard

A main terminal area, with long extensions having gates down one side. May be designated into different terminals depending on the size.

Pier

Like concourses, extensions with gates down both sides, but connected on one end by additional buildings. Each pier may be designated as a separate terminal.

Satellite

A main terminal area connected to one or more smaller terminal buildings with gates all around. Generally connected underground, occasionally by a bridge. Each satellite is generally designated a different terminal.