The name Mărțișor comes from the Romanian word for March - 'Martie' (MAR-tee-eh). The string itself is the important bit. The red part stands for life and warm spring days coming. The white part stands for winter snow melting away. Twisted together, the two strings show winter and spring tangled with each other as the seasons change.
The tradition is very old - archaeologists have found bits of similar twisted threads in Romanian sites that are 8,000 years old. For thousands of years people have made the strings themselves, often during the long winter evenings, ready to give away on the first day of March.
You usually pin the Mărțișor onto your jumper or coat. Most people wear it for the first week or two of March. Then on a certain day - usually 9 March - you tie it to the branch of a flowering tree in the garden. The idea is that the tree will then bloom strongly and bring good luck for the rest of the year.
Shops in Romania are full of Mărțișors in February. Schools sometimes have a Mărțișor table where children sell ones they have made to raise money for charity. By 1 March most people are wearing two or three on their chest - one from each grandma, one from each best friend.