The short answer
A social media dashboard is a single view, usually part of a broader scheduling or analytics tool, that pulls performance data from multiple connected platforms into one place. Instead of checking each platform's own native analytics separately, a dashboard shows the same kinds of numbers side by side across channels.
What it solves
Comparing performance across platforms by hand means opening several different apps, each with its own layout and terminology, and manually reconciling the numbers into something comparable. A dashboard removes that manual reconciliation, which matters more as the number of connected channels grows.
What to check before relying on one
Not every dashboard pulls the same depth of data from every platform. Some cover posting and basic reach well but offer weaker detail on a specific platform's more granular metrics. Worth checking that a dashboard covers the numbers that matter most for a given account before treating it as a full replacement for native analytics.