Why do we say, "I am a coin collector"? Why don't we say, "I am a coins collector"? Do you know anyone who collects just one coin? Its like saying, "I am going to get my haircut". Shouldn't it be, "I am going to get my hairscut"? Just something to think about. :kewl:
I've thought about this in terms of sports. For those of you who know me (just about nobody), I enjoy golf. We play football, play basketball, play baseball, hockey, rugby, soccer, etc., but we do not "play golf". No, we just "golf." There is nothing playful about the sport, to be quite honest. It is very brutal. Golf, indeed, separates itself from the rest of sport, as it is truly a competition against oneself. You have no opponent, save the course itself. In any other sport, you play against someone, but in golf, you play against the biggest demon: yourself. Think about it.
Okay, I thought about it and now what? Wait a minute, you're looking to be titled also I bet, now I understand what you're up to.
In the term "coin collector", the noun, coin, is acting as an adjective, while being positioned adjacent to the modified noun. When a noun acts as a adjective (giving further information about another noun) then it is called a nominalized adjective. All nominalized adjectives are given in the singular form of the noun. Thus, if you collects cars, you would be a "car collector". If you collect wines, you would be a "wine collector". When using a noun as an adjective (a nominalized adjective), you drop the plurality. If you ask why, there is no why...it is a law of English grammar. It would be like asking why 2+2=4. There is no reasoning behind it, it is simply a law of the mathematics we utilize. We could very well say II+II=IV instead. The concept is still the same, just termed differently. Hope that helps you in your language arts dilemma.
Hey Mary Anne! Errrr. Professor...... Apparently, some authors disagree with you. A fellow named Charles Rodgers has authored a book: "Coins Collecting in North India" . It is available on Amazon. https://www.amazon.com/s/ref=nb_ss_gw?url=search-alias=aps&field-keywords=coins+collecting+india