I have finished both my English essay and my history essay. The conjunction used in this sentence is -

যেসব conjunction জোড়ায় জোড়ায় ব্যবহৃত হয় তাদের Corelative conjunction বলে।
যেমন - As ... as, so ... as, both ... and, either ... or, neither .... nor, not only .... but also ইত্যাদি।

I am finished with both my English essay and my history essay. - এই sentence এ ‘‘both......and’’ corelative conjunction হিসেবে ব্যবহৃত হয়েছে।