So I just wrote about 彦(hiko) literally meaning “sun child”, used as an euphemism for a male person. Afterwards, while playing Tales of Xillia, the following word sparked my attention: 山彦.  It means echo and is apparently composed of “yama”+”hiko”=”mountain”+”sun child”.

Alright, what? Well, the mountain part is understandable, that’s where echoes often occur. But what does it have to do with “hiko?” Perhaps you’ve got a guess, but perhaps you’re as clueless as I had been. So, taking up this opportunity, I think it’s time to show you how great monolingual dictionaries are and that they’re not that hard to understand. Let’s take a look at the 明鏡国語辞典:

やま-びこ【山▼彦】
《名》
山・谷などで声や音が反響すること。
→もと、山の神の意。山の神が音声をまねると信じられていたことから。

For everyone not speaking Japanese, this translates to:

yamabiko [in kanji:山彦,彦 is not a general-use kanji]
<noun>
Echo.
→Originally meant “Mountain Deity.” The current meaning derives from the belief that it was this deity who mimicked one’s voice or sounds.

And there you have it. Keep in mind “hiko” is a fanciful way to talk about a male being, so it’s not hard to understand that word is used to refer to a Japanese deity.