Variable

A named place to store a value.

Function

A named block of reusable code.

Big-O

How cost grows with input size.

API

Application Programming Interface, a contract for using a service.

Git

Distributed version control system; the standard.

Commit

A snapshot of your code at a moment in time, with a message.

Branch

A separate line of development you can merge later.

Refactor

Improving code structure without changing behaviour.

Idempotency

Operation that yields the same result whether called once or many times.

ACID

Atomicity, Consistency, Isolation, Durability, guarantees for reliable database transactions.

Race condition

Bug where outcome depends on unpredictable timing of concurrent operations.