1. Élelem, élelmiszer and ennivaló are more or less synonyms, but we use it in different context. Öt napi hideg élelmet vittek magukkal. This means that they have probably gone for a trip, and took (cold) food with themselves which lasts for five days. (Most probably bread, sausages or some food in tin cans.) Hoztál magaddal ennivalót? Did you bring some food? (Most probably some sandwiches for the rest of the day.) Élelmiszer is officially used for the basic foods you can buy in a store, also would say ingredients, like: milk egg cheese bred butter, vegetables fruits, raw meat and frozen fish, bottled drinks, coffee powder, etc. We never use élelmiszer for the prepared/cooked foods or meals, which you can buy in restaurants. We use the word "étel" for those. Élelem and ételem ar not the same. Ételem means "my meal" or "my food", and the basic form of the word is étel (meal, food). Az én ételem kihűlt. A tiéd még meleg? (My food got cold. Is yours still warm?) Sorry for my english is not perfect.