Two More Word Origins (and one not)

Berserk comes from Old English (and ultimately Norse) berserkr, meaning 'bear shirt'--i.e., presumably, a shirt made of a bear skin. Or it could be 'bare shirt', meaning of course no shirt at all, bare-chested. Nobody knows which it is.

Jerusalem artichoke (nowadays commonly sold as a "sunchoke"). These are not artichokes nor do they  have anything to do with Jerusalem. The word is related to Italian girasole, meaning 'sunflower'. (The Italian word comes from words meaning 'turn' and 'sun'.) 

The ac- in the word acorn is the Old English word for 'oak'. 'Oak tree' was ac treo.

Pen, before it meant a writing instrument, meant 'feather'. In French (plume) and German (Feder), the word for 'pen' is still the same as 'feather'.

This is not a word origin but another case where we don't know the correct interpretation, There is in the Old English (or Anglo-Saxon) literature the phrase dæþ se bytere. We don't know if that means 'death the biter' or death the bitter (one). They didn't mark long vowels.

The (Sometimes) Oddities of Prefixes

We are all very familiar with prefixes. Many times there seem to be a pair of two opposite prefixes such as pro- and con-; in- and ex-.

Often times the two prefixes that seem to be paired seem to be opposite in meaning. In- and ex- can suggest inside and outside, as in interior and exterior. However, this is one example where you can't push this too far and make it truly general: Intrude and extrude are by no means opposite.

One perhaps amusing if (hopefully) not almost sacrilegious pair might be pro-stitution and con-stitution. Hopefully that example shows that prefixes might sometimes be opposite in meaning but are not always!