estrem
The term "estrem" is not a recognized word in standard English or in common academic or technical lexicons. It is possible that "estrem" is a misspelling of a similar-sounding word, a neologism, a term specific to a niche field, a proper noun, or a word from another language.
If "estrem" is intended to be an English word, common phonetic similarities might suggest several possibilities.
Alternatively, "estrem" could be a transliteration or a word from a language other than English. Without further