A record is one specific item in a database - one client, one job, one invoice, one task. It's a row in that entity's table, with its own values across all of its columns: a specific name, a specific amount, a specific date.
In a modern database app, everything related to a record gathers around it - emails with that client, attachments for that job, chat about that project, printed documents generated from its data. Instead of communication, documents and data being scattered across different tools, they stay together around the record they belong to.
Web forms or webhooks from an online store typically create a new record directly - a customer submits an inquiry, and the system automatically creates a record for the new job from it, with no manual retyping.
Related: Email, forms and chat in the context of a record, What is an entity, A data model that grows with the team.