[1] : The Collaborative International Dictionary of English v.0.48

main entry word \main entry word\ n.
   the form of a word that heads a lexical entry and is
   alphabetized in a dictionary; also called entry word,
   headword, and lemma.

   syn: citation form, entry word, headword, lemma.
        wordnet 1.5

   note: in different languages, different wordforms, such as
         cases for verbs, may be taken as the main entry word.
         in english dictionaries, it is the infinitive form, but
         in latin dictionaries it is usually the first person
         singular present.
         pjc
see also:
entry word headword lemma 

[2] : WordNet (r) 2.0

entry word
     n : the form of a word that heads a lexical entry and is
         alphabetized in a dictionary syn: citation form, main
         entry word
see also:
citation form main entry word 

Entry Word >> E Words
Entry Word, definition of term: Entry Word
entry+word_pag1.html

Entry >> E Words
Entry, definition of term: Entry
entry_pag1.html

Nonce Word >> N Words
Nonce Word, definition of term: Nonce Word
nonce+word_pag1.html

Microsoft Word >> M Words
Microsoft Word, definition of term: Microsoft Word
microsoft+word_pag1.html

Key Word >> K Words
Key Word, definition of term: Key Word
key+word_pag1.html

Compound Word >> C Words
Compound Word, definition of term: Compound Word
compound+word_pag1.html

Cognate Word >> C Words
Cognate Word, definition of term: Cognate Word
cognate+word_pag1.html

Port Of Entry >> P Words
Port Of Entry, definition of term: Port Of Entry
port+of+entry_pag1.html