Why is the English Horn called a horn when it is a woodwind instrument, basically a lower oboe? When compared to other horns, such as the French Horn and the Flugelhorn, it seems to be a misnomer.
Interestingly enough, the English Horn is commonly known by the French term 'cor anglais', but in fact originated in Germany! To make matters worse, the French Horn is a descendant of the English hunting horn.
The term 'horn' has had varying meanings throughout history and genre. At the most basic level, it simply refers to the cylindrical shape of an animal's horn, which would be hollowed out and turned into an instrument like the shofar. (As classified by the Hornbostel-Sachs system of musical instrument classification, all modern brass instruments are cousins or descendants of this type of instrument.) This definition was then applied to other instruments that made use of a cylindrical horn-shaped bell, whether they were "trumpets" or not.
In present-day popular music, the vernacular term has generally expanded to include all wind instruments, including modern woodwinds like the saxophone. (Basically, if the leader says "horns!" and you're not singing, playing keyboard, or holding drumsticks or a type of guitar, then they're talking to you.)
So, 'horn' on its own is not exclusive to brass instruments. However, the reason for the english horn, or cor anglais being referred to as such seems to stem from the fact that despite it being a type of tenor oboe with a bulb bell, it was similar enough to another instrument, the oboe da caccia, or "hunting horn" in Italian, that had a plainly flared bell. The name stuck when that instrument fell into disuse.
So yes, it is a bit of a misnomer! It would make much more sense to have it be part of the oboe family, as the fingerings are similar and most players of the english horn began as oboe players.
There is another variation, called the oboe d'amore ("oboe of love" in Italian), which is pitched "mezzo-soprano" between the oboe and the English horn. There is a modern oboe d'amore, but it is more often found in its Baroque version in contemporary Baroque music ensembles and early music groups. Some people conjecture that its modern name is a pun based on the name "Oboe of the Moors," meaning an instrument descended from Middle-Eastern Arabs that lived in Spain up until mediaeval times. If this is true, then the oboe d'amore would have the same ancestors as the Turkish zurna, another double-reed wooden instrument with a wide trumpet-like bell that comes down to us from antiquity. The European version, from Renaissance times, was called the shawm.
The best explanation I have heard was that the term "English" does not really refer to originating from a country, but rather angled/curved/spun as in "putting English on a ball." This was from an expert speaker at an International Double Read Society convention, so YMMV.
[As an interesting aside, one of the answers to the referenced question says 'from Fr. anglé "angled," which is similar to Anglais "English."']