Basic (basic)
Contains uppercase & lowercase letters, figures, accented characters and punctuation. These fonts also contain currency symbols ($, ¢, €, £, ¥), standard ligatures (fi, fl), common diagonal fractions (one-quarter, one-half, three-quarters), common math symbols, superscript numerals (1, 2, 3) and other symbols (including daggers, trademark, registered trademark, copyright, paragraph, litre, circled P, and "estimated" symbol, etc.).
Latin 2 (latin2)
Support for the following Central, Eastern and Baltic European languages [as well as Western]: Croatian, Czech, Estonian, Hungarian, Latvian, Lithuanian, Polish, Romanian, Serbian (Latin), Slovak, Slovenian and Turkish. In addition to 1252 Latin 1, these fonts support 1250 Latin 2, 1254 Turkish, and 1257 Windows Baltic.
Extended (extended)
Includes additional Latin characters beyond the combined
latin2 Western and Central European character sets to support languages such as Maltese and Esperanto.
Small Caps (smcp)
Fonts with small caps contain all of the
latin2 accented characters (and extended, if the base glyphs support extended) as well as the
ss01 feature to create roman numerals.
Oldstyle Numerals (onum)
A.K.A., non-lining numerals, or lower case numerals
Roman (roman)
Not a proper OT feature, is controlled by other features. In the case of roman, you can type any regular number, e.g., "2013" and by using the "ss01" (stylistic set 1) feature in an OpenType aware program such as InDesign, it will automatically be converted to a proper roman numeral. In the case of 2013, the ss01 feature would give you MMXIII without you having to know how to type roman numerals or convert arabic numerals to roman numerals. All of the fonts that have the
smcp feature also have the ss01 feature to create roman numerals. Because it's controlled by OpenType features, if you switch to a font that doesn't have roman numerals, you will still see the original numerals typed.