AWS Vocabulary: Cloud Terms Every Developer Needs in English

Amazon's virtual machine service. You launch instances with the OS, CPU, and memory you need, and pay by the hour or second.

“Spin up a t3.medium EC2 instance for the staging environment.”

A single running virtual machine on EC2. Each instance has an instance type that defines its CPU, memory, and network capacity.

“The instance ran out of memory. We need to upgrade to a larger instance type.”

A pre-configured template used to launch an EC2 instance. It includes the OS, application server, and any pre-installed software.

“Create a custom AMI with the app pre-installed so new instances are ready faster.”

AWS's serverless compute service. You deploy a function and AWS runs it in response to events without you managing any server.

“We trigger a Lambda function every time a new file is uploaded to S3.”

The unit of deployment in Lambda. Each function is a single piece of code with its own runtime, memory limit, and timeout.

“The function timed out after 15 seconds. Increase the timeout limit or optimise the code.”

The event source that invokes a Lambda function. Common triggers include S3 uploads, API Gateway requests, SQS messages, and scheduled events.

“Add an S3 trigger so the thumbnail function runs whenever a new image is uploaded.”

A collection of EC2 instances that scales automatically based on demand or a schedule. When load increases, new instances are launched; when it drops, instances are terminated.

“The auto-scaling group added three instances during the traffic spike and removed them afterwards.”

Distributes incoming traffic across multiple EC2 instances or containers. AWS offers the Application Load Balancer (ALB) for HTTP traffic and the Network Load Balancer (NLB) for TCP.

“Point the load balancer at the auto-scaling group so traffic is distributed evenly.”

AWS's object storage service. You store any file as an object inside a bucket. S3 is highly durable and used for backups, static assets, data lakes, and more.

“Upload build artifacts to S3 so all environments can pull the same version.”

The top-level container in S3. Bucket names are globally unique. Each bucket can hold an unlimited number of objects.

“Create a private bucket for database backups and a public bucket for static assets.”

A file stored in S3. An object consists of the file data and its metadata (content type, size, custom tags, etc.).

“The object key is the full path: images/2026/banner.png.”

The unique identifier for an object within a bucket. The key is the full path, including any folder-like prefixes.

“Use a key prefix like logs/2026/ to organise log files by year.”

A managed relational database service that supports PostgreSQL, MySQL, MariaDB, Oracle, and SQL Server. AWS handles backups, patching, and replication.

“We moved from a self-managed Postgres to RDS to eliminate manual patching.”

AWS's fully managed NoSQL database. DynamoDB scales automatically and offers single-digit millisecond latency at any scale.

“We use DynamoDB for the session store because it handles millions of requests per second.”

The primary resource in DynamoDB. A table stores items (records) identified by a partition key and optional sort key.

“Create a sessions table with userId as the partition key and sessionId as the sort key.”

The AWS service that controls who can do what in your account. IAM manages users, groups, roles, and policies.

“Create an IAM role for the Lambda function so it can read from S3 without hardcoded credentials.”

An IAM identity that can be assumed by AWS services, EC2 instances, or Lambda functions. Roles have policies attached that define their permissions.

“Attach the S3ReadOnly policy to the EC2 instance role instead of embedding AWS keys in the code.”

A JSON document that defines which actions are allowed or denied on which resources. Policies are attached to users, groups, or roles.

“Write a least-privilege policy that allows only s3:GetObject on the specific bucket.”

An individual action allowed or denied by a policy. Permissions follow the format service:action, for example s3:PutObject or ec2:DescribeInstances.

“The function failed because it is missing the dynamodb:PutItem permission.”

A logically isolated network you define inside AWS. Resources in a VPC can communicate privately without going through the public internet.

“Launch the RDS instance inside the VPC so only the application servers can reach it.”

A range of IP addresses within a VPC. Public subnets have a route to the internet gateway. Private subnets do not.

“Place the database in a private subnet so it has no public internet access.”

A virtual firewall for EC2 instances and other resources. Security groups control inbound and outbound traffic at the instance level.

“Update the security group to allow inbound traffic on port 443 from the load balancer only.”

A globally unique identifier for any AWS resource. Format: arn:aws:service:region:account-id:resource. Used in IAM policies and API calls.

“Copy the ARN from the Lambda console and paste it into the IAM policy as the resource.”

AWS's monitoring and observability service. It collects logs, metrics, and events from AWS resources and custom applications.

“Set up a CloudWatch dashboard to track Lambda invocations, errors, and p99 latency.”

A CloudWatch resource that watches a metric and triggers an action when a threshold is breached. Common actions include sending an SNS notification or scaling an auto-scaling group.

“Create an alarm that pages the on-call team when error rate exceeds 5% for 5 minutes.”

A time-series data point collected by CloudWatch. AWS services publish metrics automatically; you can also publish custom metrics from your application.

“Publish a custom metric for checkout success rate so we can alarm on business-level errors.”

AWS's content delivery network (CDN). CloudFront caches content at edge locations around the world to reduce latency for end users.

“Put CloudFront in front of S3 to serve static assets with low latency globally.”

The CloudFront resource you create to serve content. A distribution defines the origin (S3 bucket, ALB, etc.) and the caching and routing rules.

“Update the distribution to add a custom domain and SSL certificate.”

A geographic area where AWS operates data centres. Each region is independent. You choose a region based on latency, compliance, and cost.

“Deploy to eu-west-1 (Ireland) to comply with European data residency requirements.”

One or more discrete data centres within a region, each with independent power, cooling, and networking. Deploying across multiple availability zones increases resilience.

“Spread the RDS instances across two availability zones for automatic failover.”

A library that lets you interact with AWS services from your application code. AWS offers SDKs for Python (boto3), JavaScript, Go, Java, and more.

“Use the AWS SDK for Python to upload files to S3 from the data pipeline.”

The aws command-line tool for managing AWS resources from a terminal. The CLI uses the same credentials and permissions as the SDK.

“Run aws s3 ls to list all buckets in the account.”

The AWS tool for visualising, analysing, and forecasting your cloud spending. You can filter by service, region, tag, and time period.

“Use Cost Explorer to find which Lambda functions are driving the spike in compute costs.”