To quote Felicia:
"It's a japanese word that translates into "Bonus" or "Extra"."
You may find omakes on anime DVDs included as extras, or simply as extras in any other sense of the word.
They usually include a total change in style as well as a humoristic view. Making fun of the previous stories and such.
Kos-omak
An Arabic work that literaly translates (you mother's vagina)
However, it is used in the Arabic language to cuss someone else and is considered one of the strongest most offensive phrase you can say to a person. Always expect a fight after it.
This term has become popular on many fanart or anime sites. It is also used on various other web sites. It's a japanese word that translates into "Bonus" or "Extra". It basically involves any material on the site that does not fit into any of the other site's catagories. Such as downloads, photos, rants, or links.
An Arabic cuss word originally derived from Egyptian culture, literally meaning "your mother's pussy/vagina".
It's one of the most offensive things you can say to an Arab to the point that it can lead to fights sometimes depending on how it's used, so better watch your tongue.
It's usually used similarly to the cuss word "fuck you" in English, It may also be used as it's literal meaning depending on the context it was used in.
Example 1:
Omar: You're so bad at the game I won the match in just 10 seconds.
Ahmed: Kos omak!
(in this context it has similar meaning to "fuck you" in a less offensive manner.)
Example 2:
Wahab: To whom does this pencil belong to?
Adham: Belongs in kos omak.
(in this context it's used with the literal meaning of the word; "your mother's pussy/vagina" and thus sounding much more offensive than the other variant above. --Wahab must've picked a fight with Adham after he had disrespected him this way.)