What does 'high-order' or 'most-significant' refer to in binary numbers?

In the context of binary numbers, 'high-order' or 'most-significant' refers to the leftmost bit in the binary sequence. This bit is crucial because it carries the highest value in the number represented in binary. For example, in an 8-bit binary number, the leftmost bit represents 128 if it's a standard unsigned binary format.

The significance of the most-significant bit is that it plays a critical role in determining the overall value of the binary number, especially in signed numbers where it can indicate the sign (positive or negative) of the value. In contrast, the other bits to the right (the least significant bits) have progressively lower significance and contribute less to the total value. Understanding this concept is fundamental in areas such as computer science, digital logic design, and coding theory.