stick is a stick used to count something by scoring
a notch on the stick to represent each item. When used in a contract
, the stick was split in half lengthwise so that each party could get one, to verify
the count. (Come to think about it, it is the earliest form of copy protection, since the halves of the stick were unique to one another.)
Tallying (making a mark to count your stuff) is the earliest know form of writing.
The concept extends to notches on a belt, a gun, and a bedpost, among others. making a mark on something that you would keep as a record is almost a natural impulse. The term applies to many concepts and words we still use today. A broker handled financial transactions, and broke the tally stick for the two parties. A stock is a thick stick. (Of course, the term "scoring" still applies to a count, as does the word "tally" which means to count.)
They were used quite extensively within the British Government for tax and accounting purposes by the largely illiterate bureaucracy until 1724. The sticks were kept in storage until 1826, when it was finally decided to eliminate them. When the British government conducted the burning of the old tally sticks, the fire got out of control and burned the Parliament building to the ground.