MSB is the acronym for most significant bit. In the field of computing, the most significant bit is also called the high-order bit, and is used to refer to the bit position in a particular binary number, which has the greatest value.

On big-endian architectures, the most significant bit is also regarded as the left-most bit because of the standard in positional notation, which involves writing the digits which are more significant further to the left side. In addition, the most significant bit can also express the sign of a particular signed binary number in one’s complement or two’s complement notation. The number 0 corresponds to positive, while the number 1 means negative.

Alternatively, the acronym MSB can also stand for Most Significant Byte. Basically, MSB is the byte position with the greatest potential value in a multi-byte number. Furthermore, the plural form most significant bits, is used to refer to the bits of a certain number that includes and are closest to the MSB.

When referencing bits in a binary number, it is a common practice to designate a bit number for each bit. This bit number assignment can range from zero and above to one less than the number of bits. The order that is employed for assigning bit numbers can be in either direction depending on the context. In order to avoid confusion, the term msb is commonly used to refer to the high-order bit instead of designating a bit number.

There are also terms used to indicate the ordering of the bit sequence in the bytes that are sent in a stream or a transmission protocol. These expressions are “Most Significant Bit First” and “Least Significant Bit First.” As the names suggest, the “Most Significant Bit First” simply means that it is the most significant bit, which will arrive first; and the “Least Significant Bit First” implies that the least significant bit will be the first to arrive.