[f FLAG sb.2 + -Y1.] Cleaving readily into flags, capable of being split up, laminate.
1847. Ansted, Anc. World, iii. 23. A grayish-coloured sandy stone, often slaty or flaggy.
1877. A. H. Green, Phys. Geol. ii. § 7. 85. A rock which is regularly and not very thickly bedded, so that it can be split up into slabs for paving, is called Flaggy, or a Flagstone.
