Disuse usually refers the discontinued use of structures or equipment.
For instance, in areas where trains and subways are used, these items eventually wear out or are replaced with newer models. These older and discarded rail cars are then referred to as disused. A similar set of circumstances can be found in the use of words, ideas, and techniques.
For instance, many of the words that are used in Shakespeare's plays are no longer in everyday use and be considered disused. Likewise, some outdated medical techniques such as lobotomy and "bleeding" can be called disused techniques.