Plain-English definitions of the core AWS terms for SAA-C03 study. Simplified for learning; the AWS documentation is authoritative.
| Term | Definition |
|---|---|
| Region | A geographic area containing multiple Availability Zones. |
| Availability Zone (AZ) | One or more isolated data centres within a Region. |
| VPC | Virtual Private Cloud - your isolated private network in AWS. |
| Subnet | A range of IPs in a VPC; public (internet-facing) or private. |
| Security group | A stateful virtual firewall for instances. |
| NACL | Network ACL - a stateless subnet-level firewall. |
| IAM | Identity and Access Management - users, roles and policies. |
| IAM role | Temporary credentials assumed by services or users. |
| EC2 | Elastic Compute Cloud - virtual servers. |
| Auto Scaling | Automatically adjusts capacity to demand. |
| ELB | Elastic Load Balancing - distributes traffic across targets. |
| S3 | Simple Storage Service - scalable object storage. |
| EBS | Elastic Block Store - block storage for EC2. |
| EFS | Elastic File System - shared file storage. |
| RDS | Relational Database Service - managed SQL databases. |
| DynamoDB | Managed NoSQL key-value database. |
| Lambda | Serverless functions that run code on demand. |
| CloudFront | Content delivery network (CDN). |
| Route 53 | Managed DNS and routing. |
| SQS | Simple Queue Service - decoupling via message queues. |
| SNS | Simple Notification Service - publish/subscribe messaging. |
| KMS | Key Management Service - manages encryption keys. |
| Multi-AZ | Deploying across Availability Zones for high availability. |
| Read replica | A read-only copy of a database that scales read traffic. |
| Aurora | AWS’s managed MySQL- and PostgreSQL-compatible database. |
| ElastiCache | Managed in-memory cache (Redis or Memcached). |
| CloudWatch | Monitoring: metrics, logs, dashboards and alarms. |
| CloudTrail | Records account API activity for audit and governance. |
| API Gateway | A managed front door for creating and securing APIs. |
| ECS / EKS / Fargate | Container orchestration (ECS/EKS) and serverless containers (Fargate). |
| CloudFormation | Infrastructure as code using declarative templates. |
| NAT Gateway | Lets private-subnet resources reach the internet outbound only. |
| Internet Gateway | Connects a VPC to the public internet. |
| Direct Connect | A dedicated private network link from on-premises to AWS. |
| Site-to-Site VPN | An encrypted tunnel from an on-premises network to a VPC. |
| S3 storage classes | Tiers such as Standard, Infrequent Access and Glacier for cost vs access. |
| EBS vs instance store | Persistent block storage versus ephemeral local disk. |
| Elastic IP | A static, reassignable public IPv4 address. |
| STS | Security Token Service - issues temporary credentials. |
| Cognito | User sign-up, sign-in and identity for applications. |
| Kinesis | Real-time streaming-data ingestion and processing. |
| Well-Architected Framework | AWS design pillars: security, reliability, performance, cost, operations, sustainability. |
| On-Demand / Reserved / Spot | EC2 pricing: pay-as-you-go, committed discount, or cheap-but-interruptible. |
| SQS vs SNS | A pull-based queue (point-to-point) versus push-based pub/sub (fan-out). |