In Scala, a "stream" typically refers to an infinite or lazily-evaluated sequence of elements. Streams are a core concept in functional programming and are used to represent potentially infinite sequences of data. Unlike collections, which are eagerly evaluated, streams are evaluated only when elements are accessed, making them memory-efficient and suitable for working with large or infinite datasets.

Here are some key characteristics and uses of streams in Scala:

Laziness: Streams are lazy data structures, meaning they do not compute or store all their elements upfront. Instead, elements are computed and generated only when they are accessed. This laziness allows you to work with potentially infinite sequences without running out of memory.

Immutable: Like other functional data structures in Scala, streams are immutable. Once created, a stream cannot be modified. This immutability ensures data integrity and consistency.

Functional Operations: Streams support various functional operations similar to collections, such as map, filter, take, drop, and more. These operations are evaluated lazily, producing new streams as a result.