ACS, which was founded in 1876 and claims to be the world's largest scientific society, sued Google in 2004. The suit claimed that the free "Google Scholar" journal-search service unfairly competes with ACS' "SciFinder Scholar," which appears to be more comprehensive but charges a fee.
"SciFinder Scholar is well-known and long has been well-received throughout the academic community, and we must protect our name and the good will the tool has already achieved," an ACS representative said at the time.
But the case was quietly settled out of court in Washington, D.C., earlier this month, with Google and ACS submitting a joint two-page document that says each side will pay its own attorney fees.
"The ACS is pleased at the outcome of its lawsuit against Google," an ACS representative said in response to a query from CNET News.com. "The settlement includes a confidentiality clause and as such the ACS will have no further comment." A Google spokesman said the company was also "pleased that the case has been dismissed" but provided no further comment.
As of Wednesday, Google Scholar still exists in beta form and does not appear to have been altered in response to the lawsuit. Google says the service indexes "peer-reviewed papers, theses, books, abstracts and articles" from professional societies and other scholarly organizations.
The lawsuit had claimed trademark violation and unfair competition.
In April, Microsoft launched a rival to Google Scholar called Windows Live Academic.
CNET News.com's Anne Broache contributed to this report.