In 2 Kings 18:17 the EHV refers to a landmark in Jerusalem as the launderers field or wool-cleaners field. Shouldn’t this be either the launderer’s field or the launderers’ field?
Sometimes plural nouns being used as adjectives are mistaken for possessives. A pastors conference is not a conference belonging to one or more pastors, so no apostrophe is needed. The word pastors here functions as an adjective, telling what kind of conference this is.
In biblical passages, an advantage of the adjective construction rather than the possessive construction is that it is sometimes impossible to tell whether the possessive should be singular or plural. Even when singular or plural is indicated by the context, the point of the expression often is not possession or ownership of the place but what kind of activity is taking place there. In some cases, the term Launderers Field may simply be a place name, in which case it could be capitalized.
2 Kings 18:17 refers to the water channel from the upper pool, which is on the way to the launderers or wool-cleaners field (the Hebrew is literally on highway-of field-of launderer). The question here is not who owns the field. The launderers field is simply being used as a landmark to help readers identify the location of the water channel. It is possible that one launderer owned the field and worked there by himself, so we could translate launderer’s field. But in the context, it seems more likely that this is the area of the city where the launderers worked, the launderers’ quarter, so to speak. For that reason, EHV went with the descriptive adjective launderers rather than with the singular possessive launderer’s. Either translation is possible. The same situation exists with the potter’s field in Matthew 27:7. Interestingly, the UBS4 Greek text as it appears in the LOGOS Bible program capitalizes the term as a proper name, Potters Field. (This matches its capitalization of Field of Blood in verse 8.) Most editions and translations read potter’s field. This spelling is common enough that in English potter’s field has become a stock term that is even used as a generic term for any burial place for the poor.
In such cases, one must decide whether the point is possession or some sort of description. For many years, the baseball stadium in Detroit was named Briggs Stadium, no apostrophe. The issue was not whether Mr. Briggs owned the stadium but that it was named in his honor. St. Johns Church is not a church owned by John, but a church named in his honor, the Church of St. John.
Ram’s horn is a special case. There actually is no Hebrew word for ram in this expression. The Hebrew is the single word shofar. We translated shofar as ram’s horn to distinguish it from the regular Hebrew word for an animal horn, qeren. We probably could have (or even should have) translated it rams horn since the point is what kind of horn it is, but then many people would have wondered why there was no apostrophe. For simplicity, we choose ram’s horn as the stock name for this musical instrument. Each horn came from one ram, so we used the singular.