Wiktionary:Wiktionary is a secondary source
Wiktionary is a secondary reference. This means two things:
Wiktionary is not a primary source
Primary sources in lexicography are actual usages. If I wish to demonstrate that the word "fish" is in current use, I show an example of someone using the word "fish". The major task of a dictionary, including Wiktionary, is to gather together material from such primary sources and produce definitions, pronunciations, translations, etymologies and so forth.
It is not the task of Wiktionary to produce definitions of terms which are not used elsewhere. A term should not have an entry in the main body of Wiktionary unless it can be shown to be in use elsewhere.
Wiktionary is not a tertiary (or higher-order) source
Wiktionary must not rely on other secondary sources, such as other dictionaries, research papers on etymologies and so forth, for its material. Looking up a term in another dictionary is not meaningful research, though it may indicate whether primary sources for a word are likely to be found.
There is one significant exception to this rule: Large portions of the 1913 edition of Webster's Dictionary have been imported into Wiktionary wholesale. There is disagreement as to whether this was a good idea.