A definition for an English word can be requested by going to Wiktionary:Requested entries (English) and putting it in the appropriate section.
A word in another language can be requested by going to Category:Requested entries by language or this automatically generated list and finding the right page (or replace "English" by the appropriate language name in the above link). If the page for the language does not exist yet, you can either create it yourself or put up a request for it at Wiktionary:Tea room.
A word in a language you don't know can be requested by inserting it at Wiktionary:Requested entries:Unknown language (Latin script), (Arabic script), or (CJK script).
If you are looking for a word that captures a meaning that you have in mind, you can consult the Tea Room.
- Wiktionary:Translation requests
- Wiktionary:Tea room (for discussion of specific words)
- User-maintained lists:
- User:Connel_MacKenzie/Wantedpages replicates the late, lamented Special:WantedPages.
- User:Robert Ullmann/Missing: lists of words used in Wiktionary that lack Wiktionary entries.
- User:Brian0918/Hotlist: lists of words with entries in major dictionaries.
- User:Visviva/Tracking: lists of words lacking Wiktionary entries that are used in selected newspapers.