Short Form of a Name

The short form of a name is usually a portion of that name. It can coincide with the first part, for example, Alex derives from Alexander, Barb derives from Barbara, Deb derives from Deborah, and Mike derives from Michael. In other cases it can coincide with the central or final part of the name, for example, Beth or Lisa derive from Elizabeth, Fred derives from Alfred, Greta derives from Margareta, etc..
In most cases, the short form of the name is obviously shorter than the name. In some countries, and in some cases, the short form of the name is used as first name in its own right, and can be used in baptism ceremonies and indicated on personal documents. An example is Manuela, which is the short form of Emanuela.

Diminutive / Nickname / Pet Name

In linguistics the diminutive form is also called a pet name, and indicates a form of the name that is usually used by friends, family and loved ones. The diminutive is usually part of the name plus a suffix (last part of the name) which varies from country to country, but in other cases it can be different from or just similar to the given name. In contrast to short names, it is unlikely that this form will be used for baptisms and in personal documents.
(Spanish) CARLOS > Carlito, Carlitos
(Portuguese) CARLOS > Carlinhos, Carlito, Carlitos, Cacá, Calu

Combined or blended Name

A combined or blended name is nothing more than the union of two existing names, for example Annemarie, which is the union of Anne and Marie. Combined names can be joined or divided by a hyphen, for example Karl-Heinz / Jean-Claude, which is the combination of the same names, or completely separate but considered as a single name, as in the Brazilian names, for example, Ana Beatriz / Ana Paula. This form is also used as a given name and can be used for baptisms and in personal documents.

Suffix and Prefix

In linguistics, a suffix or a prefix is a linguistic component placed at the end or at the beginning of a theme, or root, in order to form a word. It can also be added to an existing word, forming a suffixed word by a process of derivation. Even existing names can have a prefix or suffix placed before or after the name, forming a new, indipendent name. For example, the name LAKEISHA is made up of the prefix LA- and the name KEISHA, and KEANNA is made up of the prefix KE- and the name ANNA. Here the prefix component is placed before the name. Much the same happens for a suffix placed after the name. For example, the name MARILYN is made up of the name MARY and the suffix -LYN, or SHANIKA is made up of the name SHAN and the suffix -IKA. Names with a prefix are often used by African-Americans (for example, LA- or DE-), while names with a suffix or a prefix are used in countries in the English-speaking world. Often prefixes and suffixes are dictated by fashionable syllables, giving rise to creative names. Use of these linguistic components is a recent development, so it follows that names with a suffix or aprefix are recently-coined and creative. Most of these names date from the twentieth century.