Complex sentence: The word "diaeresis" comes from Greek διαίρεσις "diairesis", noun from verb "diairein", and an example is the first two vowels in the word "cooperate".
Split into simpler sentences: The word "diaeresis" comes from the Greek noun διαίρεσις "diairesis", which derives from the verb "diairein". An example is the first two vowels in the word "cooperate".