The character 子 has different difinition in different ways. ～=子 　　◎ 古代指儿女，现专指儿子（child；son and daughter ;now referring to son ）：～女。～孙。～嗣。～弟（后辈人，年轻人）。 　　◎ 植物的果实、种子（plants‘ plants、seeds）：菜～。瓜～儿。～实。 　　◎ 动物的卵(egg)：鱼～。蚕～。 　　◎ 幼小的，小的（young、small、tender）：～鸡。～畜。～城。 　　◎ 小而硬的颗粒状的东西(small hard lump or thing in grain)：～弹（dàn ）。棋～儿。 　　◎ 对人的称呼(general term for human beings)：男～。妻～。士～（读书人）。舟～（船夫）。才～。 　　◎ 特指有学问的男人，是男人的美称（ancient term of respect for a learned man;laudatory term for a man）:孔~ 墨~ 孟~ 荀~ 韩非~。 　　◎ 姓(a surname . last name)。

sunny's reply is very good,and I give some more tips below: In English, you can from "ear" to bear,to dear, to fear, to gear, to hear,to jear(maybe a guy's name), to kear(maybe a guy's name), to Lear(Shakespeare),to mear(medical),to near,to pear, to rear,to sear,to tear,to wear,to year you can do it,so we can do it! you can combine "ear" with "a.....y",so we can combine "子" with "老,儿,孙,妻,筷,桌,瓶,本,盒,杯,被,单,柜,孔,孟,庄,韩非,荀,墨,亲,钳,班,板,包,豹,才,菜,..............................................." LOL~~~~~~~~~~~~!!

just something to indicate a noun(most for noun),like -tion or -ce in English.But there's no special rule for using it,that is to say,not every noun ends with something like that.It's quite oral a character...棋子，ＣＨＥＳＳ；仙子，ＦＡＩＲＹ　ＭＡＩＤ；ＥＴＣ And "子"alone mean son ;it also means "you" in ancient Chinese,something like "thee" or "thou",for there's no difference between objective and subjective in Chinese. I only know these .Hope they can help you.