What is a primary source?

Each academic discipline creates and uses primary and secondary sources differently; the definition of a primary source only makes sense in the context of a specific discipline or field of inquiry.
In the humanities and the arts, a primary document might be an original creative work.
It might be a part of the historical record written about, or in proximity to, an event.
In the sciences, it might be a publication of original research.

Here are two definitions that try to capture the elusive nature of primary documents:

A definition from Cornell: Primary sources are the main text or work that you are discussing (e.g. a sonnet by William Shakespeare; an opera by Mozart);
actual data or research results (e.g. a scientific article presenting original findings; statistics);
or historical documents (e.g. letters, pamphlets, political tracts, manifestoes).
["What is a Source?" Recognizing and Avoiding Plagarism. Cornell University. College of Arts and Sciences.]

A definition from Yale: "A primary source is firsthand testimony or direct evidence concerning a topic under investigation. The nature and value of a source cannot be determined without reference to the topic and questions it is meant to answer. The same document, or other piece of evidence, may be a primary source in one investigation and secondary in another. The search for primary sources does not, therefore, automatically include or exclude any category of records or documents."
[Yale University Library Primary Sources Research Colloquium in History]

with thanks to Michael Engle, Cornell reference librarian

Examples of online Primary Sources

American Memory: Historical Collections for the National Digital Library.
Washington: Library of Congress, National Digital Library Program, 1994- .

Making of America: the Cornell University Library MOA collection.
Ithaca, NY: Cornell University Library, 1996- .

What kind of source is this?

Follow the link: "Italian Macaroni," (July 1893)

And this:  "The Italians and the Organ-Grinders" (1873)

Examples of news and periodicals as Primary Sources

Primary? secondary? both? when?

Gebhart, John C.  The Growth and Development of Italian Children in New York City. Publication no. 132.  New York:  New York Association for Improving the Condition of the Poor, 1924.  Olin RJ 206.D81 no. 1-10 (housed at Library Annex).

Italians in the United States:  A Repository of Rare Tracts and Miscellanea.  The Italian-American Experience.  New York:  Arno Press, 1975.  Library Annex E 184 .I8 I875.

Cordasco, Francesco. Italian Americans:  A Guide to Information Sources.  Volume 2 in the Ethnic Studies Information Guide Series.  Detroit:  Gale Research Company, 1978.  Olin Z 1361.I8 C792.