Originally posted by Madhu Juneja:
2 tier architectures have client application on tier 1 and database on tier 2. Presentation, Business Logic, Data Model Processing is all in tier 1. Hence the client is termed as "Fat Client".
3 tier architectures have client application on tier 1 and business logic on tier 2 and database on tier 3. Presentation and business logic resides in a different tier. Hence Client is termed as "thin client".