What is “the Lateran Council” (medieval context) generally?

The story behind the answer

Held at the Lateran Basilica and palace in Rome, these were formal assemblies of bishops and other prelates convened by the pope to decide doctrine, discipline, and church governance—among the most authoritative gatherings in medieval Christendom. Their decrees shaped canon law and everyday religious practice across Europe.

Notable examples include the First Lateran Council (1123), which ratified the Concordat of Worms ending the Investiture Controversy, and the Fourth (1215) under Innocent III, which defined transubstantiation, mandated annual confession and Easter communion, and set wide-ranging reforms. While the Lateran Palace was indeed a papal residence, the councils themselves were deliberative synods, not a royal assembly or a theological school.