Aggregate

Aggregate is a term with multiple related meanings across fields. Broadly, it denotes a collection of distinct items treated as a whole, or a material composed of numerous particles bonded together. The word comes from the Latin aggregare, meaning to bring together.

In construction and geology, an aggregate is a granular material used in building and engineering. It includes natural materials such as sand, gravel, and crushed stone, as well as manufactured particles. Coarse aggregate refers to larger fragments; fine aggregate to sand and finer material. Aggregates serve as the bulk filler in concrete and asphalt, as well as components in drainage layers and foundations. Their performance depends on properties like size grading, cleanliness (often measured by clay, silt, and dust content), strength, and moisture content. Standards bodies publish specifications for aggregate quality and gradation to ensure predictable behavior in mixtures.

In data processing and computer science, aggregation refers to operations that summarize or roll up data from many records into a smaller number of values. Common aggregate functions include sum, average, count, minimum, and maximum. Aggregation can be performed by database queries (group by), spreadsheet formulas, or distributed processing frameworks and data cubes. Aggregated data reduces detail while preserving overall trends and totals.

Other uses include economics, where aggregate denotes a total measure across an entire economy, such as aggregate demand or aggregate supply. In general usage, to aggregate means to gather or merge items into a single entity; an aggregate can also describe something formed from many parts, such as an aggregate rock in geology.