IMPORTANT NOTE:

In terms of countablity, nouns are categorised into two types: 1⃣. Countable nouns (eg. House, boy, pen, etc.) 2⃣. Non-countable nouns Non-countable nouns, also known as mass nouns, denote anything that cannot be counted, like milk, sugar, water, happiness, etc. These types of nouns work in a similar way in Arabic as they do in English, so they do not have a plural form because they cannot be counted. Therefore, it's incorrect to say, milks, sugars, waters, happinesses, etc. HOWEVER, when these nouns refer to distinct quantities or types, THEY MAY BE COUNTABLE; eg. I bought some sugar, I ordered two coffees, etc. For this reason, I have given plural forms for the mass nouns such as: سكر، حليب، لبن... And the same with verbal nouns (مصادر); they don't have plural forms unless the speaker intends distinct types, for example: إملاءات