GCB stands for "Grand Cross of the Order of the Bath" which is a prestigious British order of chivalry. This title is bestowed upon individuals who have made significant contributions in various fields such as political, military or civil service. While the term GCB itself has no synonyms, the term "knighthood" is often used to describe an individual who has received this honor, as well as other British orders such as the Order of the British Empire or the Order of St. Michael and St. George. Other terms that can be associated with GCB include "honours" or "awards". It is important to note that GCB is a specific order of chivalry and should not be confused with other titles or honors.