Splunk macros make SPL shorter and reusable by encapsulating frequently used search fragments and allowing them to be inserted into other searches. A macro can contain filters, field calculations, constraints, or larger portions of SPL that would otherwise need to be duplicated across multiple detections, reports, and dashboards.

Macros are typically invoked using backticks, conceptually:

search index=security | security_filter``

The macro is resolved at search execution time into the SPL definition associated with it. Parameterized macros can also accept arguments, allowing common search logic to be reused with different values.

This is particularly important for detection engineering because centralized reusable logic reduces duplication. If ten correlation searches rely on the same constraint, a macro allows the engineer to maintain that logic centrally rather than changing all ten searches independently.

Although macros are themselves Splunk knowledge objects, Knowledge objects is too broad for the question. Lookups add external or maintained contextual data to events, while commands such as stats, eval, or tstats perform specific SPL operations rather than serving as reusable search substitutions.

Study Guide topics: SPL macros, reusable searches, search maintainability, knowledge objects, detection engineering efficiency.