API
Application Programming Interface. A way for different software programs to talk to each other. Like a waiter that takes your order to the kitchen and brings food back.
Auto Scaling
Automatically adjusts the number of servers based on demand. Adds servers when busy, removes them when quiet. Amazon EC2 Auto Scaling does this.
Availability Zone
An isolated data center within an AWS Region. Deploying across multiple AZs protects your app from a single data center failure.
Bandwidth
The amount of data that can be transferred in a given time. Like the width of a highway — wider means more cars (data) can move at once.
CapEx
Capital Expenditure. Money spent upfront to buy physical assets like servers and hardware. You own it but pay everything at once.
CDN
Content Delivery Network. A network of servers around the world that cache and deliver content to users from the closest location. Amazon CloudFront is AWS's CDN.
CIDR
Classless Inter-Domain Routing. A way to define a range of IP addresses. Used in VPC to define your network's IP address range.
Container
A lightweight package that includes everything an application needs to run — code, libraries, and settings. Containers run consistently on any system.
DDoS
Distributed Denial of Service. A cyberattack where hackers flood your website with traffic to make it crash. AWS Shield protects against DDoS attacks.
DNS
Domain Name System. Translates human-readable website names (like amazon.com) into IP addresses that computers understand. Amazon Route 53 is AWS's DNS service.
Docker
The most popular tool for creating and running containers. Packages your application so it runs the same everywhere.
Encryption Key
A piece of data used to encrypt and decrypt information. AWS KMS manages encryption keys. Without the key, encrypted data is unreadable.
Hybrid Cloud
Using a mix of on-premises infrastructure and public cloud services together.
Hypervisor
Software that creates and manages virtual machines. AWS manages the hypervisor on EC2 hosts. You never interact with it directly.
IAM Policy
A document that defines permissions — what actions are allowed or denied on which AWS resources. Written in JSON format.
IP Address
A unique number assigned to every device on a network. Like a mailing address for computers. AWS uses IP addresses to route traffic.
JSON
JavaScript Object Notation. A simple text format used to store and exchange data. AWS uses JSON for IAM policies and CloudFormation templates.
Latency
The time it takes for data to travel from one point to another. Low latency means fast response. High latency means slow response.
Load Balancer
Distributes incoming traffic across multiple servers so no single server gets overwhelmed. Amazon ELB is AWS's load balancing service.
Microservices
Breaking an application into small, independent services that each do one thing. Easier to update and scale than one big application.
Multi-Factor Authentication
Requiring two forms of proof to log in — usually a password plus a code from your phone. Makes accounts much harder to hack.
NoSQL
A type of database that doesn't use the traditional table/row/column structure of SQL databases. Amazon DynamoDB is a NoSQL database. Faster for certain use cases.
Object Storage
A type of storage that manages data as objects (files with metadata). Amazon S3 is object storage. Different from block storage (EBS) or file storage (EFS).
On-Premises
Infrastructure that you own and manage yourself in your own building or data center. The opposite of cloud.
OpEx
Operating Expenditure. Money spent on ongoing services or subscriptions. Like a monthly bill. Cloud computing is OpEx — you pay as you go.
Region
A geographic location where AWS has data centers. Examples: US East (N. Virginia), Europe (Ireland), Asia Pacific (Tokyo).
Root Account
The main AWS account created with your email address. Has unlimited power. Should be locked away and almost never used.
RPO
Recovery Point Objective. How much data you can afford to lose in a disaster. If RPO is 1 hour, your backups must run at least every hour.
RTO
Recovery Time Objective. How quickly you need to be back up and running after a disaster. Lower RTO = faster recovery = more expensive solution.
S3 Bucket
A container in Amazon S3 where you store files (objects). Like a folder but in the cloud. Each bucket has a globally unique name.
Serverless
A cloud model where you run code without managing any servers. AWS automatically handles all the infrastructure. You only pay when your code actually runs.
SLA
Service Level Agreement. A commitment from AWS about uptime and performance. For example, Amazon S3 guarantees 99.99% availability.
SQL
Structured Query Language. The language used to communicate with relational databases like MySQL and PostgreSQL. Used with Amazon RDS and Aurora.
SSL/TLS
Security protocols that encrypt data sent over the internet. HTTPS uses TLS. The padlock in your browser means TLS is active.
TCO
Total Cost of Ownership. The full cost of a technology solution including hardware, software, staff, facilities, and maintenance. Used to compare on-premises vs cloud.
VM
Virtual Machine. A software-based computer that runs inside a physical computer. Amazon EC2 instances are virtual machines.
YAML
Yet Another Markup Language. A human-readable format for writing configuration files. AWS CloudFormation supports YAML.