TESSA stands for Tax-Exempt Special Savings Account. It was a kind of savings account in Britain, and it existed from 1991 to 1999. The deal was this: if you put money in a TESSA and left it there for five years, the government did not take tax on the interest the money earned. If you took the money out early, you lost that benefit. So it was a way for ordinary people to save a modest amount of money and keep all of it. In 1999 the government stopped opening new TESSAs and replaced them with ISAs (Individual Savings Accounts), which work in a similar way but with more freedom. So today the word is history. You meet it when you read about British money in the 1990s, or when an older British person talks about how they saved back then. It is written in capital letters because each letter comes from a word, but people say it as a name, 'TESS-uh', not letter by letter. Note that Tessa is also a common woman's name in English (short for Teresa) — the account was probably named to sound friendly like that, and British newspapers at the time made jokes about it.