A fleuron is a typographic element, or glyph, used either as a punctuation mark or as an ornament for typographic compositions. Fleurons are stylized forms of flowers or leaves; the term derives from the Old French word floron for flower. Robert Bringhurst in The Elements of Typographic Style calls the forms "horticultural dingbats." It is also known as a printers' flower, or more formally as an aldus leaf (after Italian Renaissance printer Aldus Manutius), hedera leaf, or simply hedera (ivy leaf) symbol.
One of the oldest typographic ornaments, in early Greek and Latin texts, the hedera was used as an inline character to divide paragraphs, similar to the pilcrow. It can also be used to fill the whitespace that result from the indentation of the first line of a paragraph, on a line by itself to divide paragraphs in a highly stylized way, to divide lists, or for pure ornamentation.
In more modern historic books, line breaks became more common as paragraph dividers, and fleurons became popular to create ornamented borders.
Fleurons were crafted the same way as other typographic elements were: as individual metal sorts that could be fit into the printer's compositions alongside letter and numbers. This saved the printer time and effort in producing ornamentation. Because the sorts could be produced in multiples, printers could build up borders with repeating patterns of fleurons.