When a sol is colloidally unstable the formation of aggregates is called coagulation or flocculation. Some authors distinguish between coagulation and flocculation, the latter implying the formation of a loose or open network which may or may not separate macroscopically. The loose structure formed in this way is called a floc.
Source:
PAC, 1972, 31, 577. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry' on page 610 (https://doi.org/10.1351/pac197231040577)