This is the 1276th most frequent Russian word.
пояснили
"Пояснили" means "explained."
In this sentence, 'пояснили' is used to indicate that the subjects ('они') provided a detailed explanation to clarify the term's meaning.
Они подробно пояснили мне значение этого термина.
They explained to me in detail the meaning of this term.
Here, 'пояснили' implies that the speakers ('мы') clarified or articulated their demands to ensure mutual understanding in the negotiation context.
Мы пояснили наши требования на переговорах.
We clarified our requirements during the negotiations.
The usage of 'пояснил' in this sentence shows the action performed by the teacher to make the reason comprehensible to the listeners about the importance of studying grammar.