most significant bit (MSB)
The Most Significant Bit (MSB) is the bit with the highest significance in the binary representation of a numerical value.
The opposite of the Most Significant Bit (MSB) is the Least Significant Bit( LSB), which is the bit with the lowest significance.
In binary notation, the Most Significant Bit is always on the far left, which is why it is also called the Left Most Bit in English. In normal notation, the Most Significant Bit is the first bit.