Can you give the Webster's Dictionary definition of 'svedberg unit'?

The definition of "dictionary" is in the dictionary, and so is the definition of "definition".

a reference book containing an alphabetical list of words with information about them

A definition for diconary is a reference that tells you the meanings, parts of speech, sometimes a sentence using the word, and how to pronounce the word).

A dictionary is where you find a definition

A dictionary definition is a carefully thought out but succinct explanation of the meaning of a word or phrase, such as may be found in a good dictionary.A dictionary definition is a description or...