Bind literally means to tie or secure, as with a rope or cord. A secondary meaning is to compel or obligate.
In Bible times, a yoke was essentially a Rabbi‘s teaching of what was prohibited and what was allowed, according to his interpretation of Scripture. The process of ascertaining what things were prohibited, was the act of binding. To bind something, then was to prohibit it, that is, to hold to it tightly. To bind implies an obligation of performance.
Jesus‘ yoke was light; there were only a few things he wanted to bind, that is, to prohibit.
Contrast to loose.