Data lake
A store of raw data in every format, kept cheaply at full size so it can be analyzed later.
What it tells you about a developer
Data lake experience marks a data engineer, the person who builds the plumbing that moves and stores raw data at scale. It usually comes with pipeline tools, big-data processing, and cloud storage depth. It sits on a different rung of the data stack than warehouse and SQL analytics work, and the two are worth telling apart on any data req.
A data lake collects data exactly as it arrives: logs, events, exports, images, whole database copies. It lives in object storage, so keeping everything is cheap, and structure gets applied later when someone asks a question. Companies build lakes when data outgrows what a warehouse economically holds. The lakehouse pattern adds warehouse-style tables on top.