span
Associates style information or a name or id to the enclosed text.

attributes

id
Provides an element with a unique name within a single document. This is especially useful in works with extensive cross-referencing and linking, such as dictionaries, encyclopedias, or travel guides. Use of ids  simplifies linking and updates.
name
Affiliates an element with name.
class
Affiliates an element with class.
style
Attaches a list of inline (name:value paired) CSS properties to a specific tag, for example: style="name:value;name:value"
Note: Media types other than "text/x-oeb1-css" will be ignored with a warning in a document of type "text/x-oeb1-document".
title
This attribute is ignored.