TSA typically stands for Transportation Security Administration. If you’re asking in a different context, here are a couple of common alternatives:

• In aviation and security contexts (especially in the United States): Transportation Security Administration.

• In oil and gas or airspace contexts: Temporary Segregated Area (used in some aviation or regulatory documents).

If you had a specific context in mind (country, industry, or a document where you saw it), tell me and I’ll tailor the answer.