Big-Endian refers to the way that data is sequentially stored in computer memory. Just as in books or magazines, where the first word appears in the top-left-hand corner of each page, the data in a big-endian system is organized such that the most significant digits or bytes appear in the upper left corner of a memory page, while the least significant ones appear in the bottom right-hand corner.
Note: This is in contrast to Little-Endian systems.
Source: Big-Endian