The amount of data that can be processed or transmitted in a given time period. Like the number of cars that can pass through a tunnel per hour.
A database with high throughput can process thousands of transactions per second during peak shopping periods.
Throughput is a performance metric (data or operations per unit time), not a single cloud service. All major clouds expose throughput metrics across networking (bandwidth), storage (MB/s, IOPS), and databases/queues (requests or transactions per second) via their monitoring tools and service-specific limits.