Lambda
In plain terms
A small anonymous function, or a serverless function service.
Going deeper
As a language feature, a lambda is a short unnamed function you pass around inline. As AWS Lambda, it's a service that runs your function on demand without managing servers. Context tells you which is meant.
Under the hood
As a closure it captures surrounding variables; as AWS Lambda it's event-driven and stateless, integrating with triggers and bound by timeout and memory limits.
Examples
map(lambda x: x*2, nums); AWS Lambda triggered by S3 upload or API Gateway.
Think of it like...
Like a sticky note with a quick instruction: small, unnamed, and handed off to whoever needs to act on it right then.