"Tat" has multiple meanings depending on the context. Here are some of the most common definitions:

• Tatting: Tatting is a technique for making lace by hand, using a shuttle and thread. "Tat" can be used as a verb to describe the act of tatting, or as a noun to describe the resulting lace.

• Low-quality items: "Tat" can be used as a noun to describe items that are cheap, of low quality, or in bad condition. This usage is informal and more common in British English.

• Tattoo: "Tat" can be used as a slang term for a tattoo, either as a noun or a verb.

• Thematic Apperception Test (TAT): The TAT is a psychological test that involves showing subjects a series of ambiguous pictures and asking them to tell a story about what is happening in each picture. The stories are then analyzed to gain insight into the subjects personality, motivations, and thought processes.

• Turnaround Time (TAT): In a medical laboratory setting, TAT refers to the period of time between when a sample is received and when the test results are reported. The exact definition of TAT can vary depending on the context and the needs of the clinician or laboratory personnel.

In summary, "tat" can refer to a type of lace-making, low-quality items, tattoos, a psychological test, or a measure of time in a medical laboratory setting.