Flagstone and Slab

Flagstone noun - Stratified stone that splits into pieces suitable as paving stones.

Slab and flagstone are semantically related. in paving stone topic. In some cases you can use "Slab" instead a noun "Flagstone", when it comes to topics like paving slab.

Slab noun - Block consisting of a thick piece of something.

Flagstone and slab are semantically related. You can use "Flagstone" instead a noun "Slab".