One For All

 לְזֹאת֙ יִקָּרֵ֣א אִשָּׁ֔ה כִּ֥י מֵאִ֖ישׁ לֻֽקְחָה־זֹּֽאת.  Rashi says that the name אשה is לשון נופל על הלשון from איש.  Howevee, man is referred to as אדם, not as איש.  Why is man called אדם and not איש?  The Gemorah in Yevamot (61a) says אתם קרויין אדם ואין העובדי כוכבים קרויין אדם.  Why are gentiles not called אדם?  The word אדם is used both to refer to a single individual or to a group of people, it is both the singular and plural form.  The word איש when used in plural form becomes אנשים.  As explained before, the concept of a tzibbur, of many individuals making up one group is only applicable by Jews, not by gentiles.  That is why gentiles are not referred to as אדם because they lack this quality of being able to be a group, to be many אדם as one.  (See here different sources for this idea.)  The possuk says in Tazria (13:2) אדם כי יהיה, it uses the terminology of אדם, why?  The Sefer Apiryon (of author of Kitzur Shulchan Aruch) uses the above idea to explain.  The sin of loshon harah, one of the causes of tzaras is when one causes a separation between people. However, gentiles, whom lack the quality of a tzibbur are not stricken with loshon harah for they are never together as a tzibbur anyway.  That is why the possuk says אדם, because you are fit to be אדם, to be together as one group, and you violated that, oyu will be stricken with tzaras. That is why the possuk refers to man as אדם, because it is since he is a אדם, since he needs to be part of a group, that he needs a partner. (Otzar HaTorah.)  Built into the very creation of mankind is the need to be part of a group.