What does -est mean?

Answer 1

If you mean the three letters, I can't help. But the word 'est' means 'is' in French and Latin.

In Spanish, este/esta/esto means this male/female/neuter; and

'esta' (with an accent over the 'a') = you (singular formal)/he/she/it is

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Another Viewpoint: The answer is quite likely to be: the standard abbreviation for Eastern Standard Time. That's the well known time zone in the USA.

However, the question is ambiguous.
It would depend on where you see the word. It could be a French word:

Est is either the cardinal direction east, or the verb être (to be) conjugated to the third person singular.

Je vais aller à l'est de Montréal; I am going to go east of Montréal.

Le chat est un animal féroce; A cat is a ferocious animal.

Unfortunately, the question is ambiguous. It could be about languages such as French or Latin. Also, it could be an abbreviation.

Answer 2

The word este is from the Spanish language. This word translates into English as the word this and into Latin as the word hoc.

Answer 3

EST stands for Eastern Standard Time.