Final answer:
The italicized abstract noun in the sentence is 'brave', which represents a quality and cannot be seen or touched.
Step-by-step explanation:
In the sentence 'Throughout the entire kingdom, none was as brave as Sir Lancelot, the famous knight.', the italicized abstract noun is 'brave'. An abstract noun refers to ideas, qualities, and conditions - things that cannot be seen or touched, and 'brave' fits this category as it is a quality. On the other hand, 'kingdom', 'Sir Lancelot', and 'knight' are all concrete nouns because they refer to physical things or entities that can be observed with the senses.