Word introspection facilities and implementation details are found in the words vocabulary.

Word objects contain several slots:

name	a word name
vocabulary	a word vocabulary name
def	a definition quotation
props	an assoc of word properties, including documentation and other metadata

Words are instances of a class.

word

word? ( object -- ? )

Words implement the definition protocol; see Definitions.
Looking up and creating words
Uninterned words
Word properties
Word implementation details