If the unit of a certain number is larger than that of another number then the number is called more significant. When writing ten past three after noon as 15:10, than the 15 is more significant than the 10, since incrementing the 15 to 16 increases the time even if the 10 is decremented to 9. 16:09 is later than 15:10.
In computer science, for historical, literary and arbitrary reasons, a way of writing where the more significant number comes first is called big endian. The more systematic term is most significant first (MSF). The opposite is little endian or most significant last (MSL).
Using a system that does neither is sometimes jokingly called middle endian. It is considered stupid.
Why americans are stupid
When writing dates, americans write: September 12, 1999. The least significant part, the days, is in the middle. That is stupid.
Why europeans are stupid
When writing addresses, europeans write: Montessorilaan 3, Nijmegen. The least significant part, the street number, is in the middle, which is stupid.
Why romans are stupid
Gaius Iulius Caesar's given name was Gaius. His family name, the name he shared with his father and is uncle, was Caesar. His clan name, the name he shared with his more distant relatives, was Iulius, which is stupid.
Why modern names are stupid
Most people nowadays write names like John Smith Junior. The family name is the most significant part. It is in the middle. It is more significant than either John or Junior. This is stupid.
Why everyone is stupid
When people write URL's they write something like: www.socsci.ru.nl/wilberth/opinion/endianness.html. The most significant part, the country, is in the middle, which is stupid.