tā / zài / xìn / zhōng / gōngjìng / de / chēng / nà / wèi / niánzhǎng / de / tóngmén / wéi / yàn / xiōng

他在信中恭敬地称那位年长的同门为砚兄。

In the letter, he respectfully addressed the older fellow student as yànxiong.