San (さん) is the most common honorific and is a title of respect. It is used for the surnames or given names of both males and females. Although in translation san is usually rendered as acommon courtesy title like "Mr." or "Ms."
San may also be used in combination with nouns describing the addressee or referent other than the person's name; for example, a bookseller might be addressed or referred to as honya-san ("bookstore" + san), and a butcher as nikuya-san ("butcher shop" + san).
Sama (様) is the formal version of san. This honorific is used primarily in addressing persons much higher in rank than oneself and in commercial and business settings to address and refer to customers. It also appears in words used to address or speak of persons or objects for which the speaker wishes to show respect or deference, such as okyaku-sama (customer). Additionally, Japanese Christians will refer to God in prayer as Kami-sama.
Kun (くん) is an informal honorific primarily used towards males. School teachers typically address male students using kun, while female students are addressed as san or chan. The use of kun to address male children is similar to the use of san when addressing adults.
While there is no direct translation into English of "kun," I usually use "little."
Chan (ちゃん) is a diminutive suffix. It is an informal version of san used to address children and female family members. It may also be used towards animals, lovers, intimate friends, and people whom one has known since childhood. Chan continues to be used as a term of endearment, especially for girls, into adulthood.
"Pet names" are often made by attaching chan to a truncated stem of a name. This implies even greater intimacy than simply attaching it to the full name. So for example, a pet rabbit (usagi) might be called usa-chan rather than usagi-chan.
While there is no direct translation into English of "chan," I usually use "little."
In the same way that chan is a version of san, there is also chama from sama, typically used for an older person. There is also the much less frequently used tama, which is the most childish. This form is usually used by young children for older siblings (like "Onii-tama", meaning "big brother"), or someone they admire.
Playful variations of chan include chin (ちん), tan (たん), and chama (ちゃま). Chin and tan are mispronunciations stereotypically attributed to small children and are thus perceived as baby talk, hence their association with cuteness.
I typically literally translate "tan" as "widdle," a mispronunciation of "little."
Source: Wikipedia: Japanese Honorifics.
Chibi (ちび, can also be written 禿び) can mean "short person" or "small child." Its meaning is of someone or some animal that is small. It can be translated as "little," but is not used the same way as chiisana (tiny, small, little in Japanese). Other translations of the word include: bitsy, brat, runt, shorty, shrimp, squirt.
Hamu or hamuhamu or almost anything beginning with "hamu" usually refers to "hamster."
Usagi or just "usa" usually refers to bunny or rabbit.
It is common for words to be abbreviated as just the first half. An often used example is "gothloli" which is abbreviated from "gothic lolita," a fashion trend in Japan. In this example, the first half of each word is taken and combined to form a new word.
There are sounds for almost anything in the Japanese language. A lot of character names have puns with relations to their respective sounds.