The kanji 息 means “son” in this common word:
息子 (musuko: son) son + child
Hmm, 子 is quite often ko, as in 子供 (kodomo: child, child + plural suffix). But 息 is never musu, so this must be ateji. Not surprising, considering how old a word 息子 probably is.
When you invert 息子, you produce another word with the same meaning:
子息 (shisoku: son) child + son
Now 息 has its real on-yomi (SOKU), as does 子 (SHI), so the world makes sense again! Ateji feels so disorienting, doesn’t it?
One more family word:
息女 (sokujo: daughter) child + female
Here, too, all the yomi check out; this is an on-on combination.
Now, let’s take a seemingly huge leap from talk of children to a discussion of finance. Check out this word:
利息 (risoku: (bank) interest) interest (on money) + interest
In addition to all its other definitions, 息 can mean “interest.” According to one dictionary, the original meaning of “breath” extended to the meaning of “multiplying,” in terms of both human reproduction and the accrual of monetary value.
Actually, maybe children and finance aren’t as far apart as one would think. After all, there are “parent companies” (親会社, oyagaisha: parent + company (last 2 chars.)) and “child companies” (子会社, kogaisha: child + company (last 2 chars.)).
