Gender of Nouns
The basic gender of nouns in Arabic is the masculine gender. This was expressed by the classical Arab linguists in their famous quote “the origin regarding nouns is masculinity, and femininity is a branch.”
Being so, nouns are supposed to be masculine unless there is a feminine marker affixed to them.
However, there is a marked exception to this rule, which is the irregular plural nouns (collective nouns). Irregular plural nouns are grammatically singular nouns that indicate plural objects. These nouns are feminine without having feminine markers, and they cannot take feminine markers because they are feminine already.
Other than that, most of the nouns without feminine markers are masculine.
Here is the rule:
Most feminine nouns other than the irregular plurals can be identified by spotting feminine markers affixed to them. There are few feminine nouns that do not carry such markers.
Masculine singular nouns have no markers. However,since that the overwhelming majority of feminine nouns (other than their regular plurals) carry feminine markers, masculine nouns can be identified by the lack of feminine markers.
There are three feminine markers: