A hauberk is a full length coat made of maille usually worn over a gambeson (a padded jacket). A hauberk usually extended to the knee and was split in the front and back to the crotch -- allowing the wearer to ride a horse. The sleeves could extend to the elbow or wrist.
This type of armour was popular in the 11th century and the early part of the 12th century as oft times the sole body armour worn. Chausses appear in the 11th century in an abbreviated form and become more prevalent in the late 12th and 13th centuries.
A shorter maille shirt which extended only to the waist was called a byrnie.