Use System font
To choose the dock text style from a list of presets, rather than manually choosing a font, size and style, check this box.
Font
To change the font used to draw the names of dock items, select a font from this popup menu.
Size
To change the size of the font used to draw the names of dock items, select a size from this popup menu.
Only available if the "Use System font" option is not selected.
Style
To change the style of the font used to draw the names of dock items, set the options in this popup menu.
Only available if the "Use System font" option is not selected.