An M with a small letter or set of letters above it stood for tens of thousands and higher. (Confusingly, in this instance the M represented the Greek ancestor of “myriad,” not the number 40.) ...

Instead, this letter has its origin in an ancient Greek symbol called a 'Christogram'. According to the expert, the nickname ...

Like Roman numerals, their system borrowed letters; like the Arabic numerals we still use, it only needed one symbol for each decimal place. In the 6th century BCE, the Greek alphabet used 24 letters.

Instead, this letter has its origin in an ancient Greek symbol called a 'Christogram'. According to the expert, the nickname emerged from a long-forgotten joke about Jesus' initials.