"lox": From Yiddish לאַקס (laks, “salmon”), from Old High German lahs, from Proto-Germanic lahsaz (“salmon”), from Proto-Indo-European laḱs- (“salmon, trout”). Cognate to Icelandic lax, German Lachs. More at lax.
It had a number of sound changes in between, and modern English "lox" just coincidentally resembles PIE's "*laḱs-". It should also be noted that the "k" is palatized, meaning it'd be pronounced more like "lakys" or "laksh".
This is fascinating to me. There's also "lax" from Old Norse, which also means "salmon". There's an Irish town near Dublin named "Leixlip" which comes from "Lax Hlaup", meaning Salmon Leap. It's also the location of some of Intel's big fabrication plants, to bring this back to technology for no good reason.
Wonder if HN can display Norse runic characters. This is the name "Lax Hlaup" in the Younger Futhark runic alphabet: ᛚᛅᚼᛋ ᚼᛚᛅᚢᛒ
It seems like the most significant change is the series of values of that consonant. I don't think the -az in Germanic is significant here because it's a separate inflectional morpheme (and can be ø in the vocative, and in nouns in subsequent Germanic languages).
I'd agree that there's an element of chance in what's happened to the k since it didn't necessarily have to change back to resemble the PIE form, but I'm not sure I see the other changes as ever having moved far from PIE at all.
It had a number of sound changes in between, and modern English "lox" just coincidentally resembles PIE's "*laḱs-". It should also be noted that the "k" is palatized, meaning it'd be pronounced more like "lakys" or "laksh".