The abbreviation "st" has multiple full forms depending on the context in which it is used. Some of the most common full forms of "st" are:

• Stone: This is a unit of weight used in the UK, and "st" is used as a written abbreviation for it.

• Scheduled Tribe: In India, "ST" is used as an abbreviation for Scheduled Tribe, which refers to a group of indigenous people recognized by the government as having a distinct culture, language, and identity.

• Street: "St" is also used as an abbreviation for "street," which refers to a road or public way.

• State: "ST" can also stand for "state," which is a political unit or subdivision of a country.

• Saint: "St" can be used as an abbreviation for "saint," which is a title given to a person recognized as having a high degree of holiness or virtue.

• Standard Time: "ST" can also stand for "standard time," which refers to the time used in a specific region or country as the official time.

• Science and Technology: "ST" can also stand for "science and technology".

• Short-Term: "ST" can also stand for "short-term".

It is important to note that the full form of "st" can vary depending on the context in which it is used.