A subsidiary of Acacia Research Corporation, easily one of the world’s most annoying patent trolls, has managed to force Amazon.com into settling a pending patent lawsuit.

The subsidiary, Adjustacam LLC, originally filed suit against dozens of retailers in July 2010, including Amazon, Dell, Wal-Mart, Newegg.com, Eastman Kodak, Target, Sears, Overstock.com and Radioshack.

Last week, Acacia announced that it had reached a settlement agreement with other defendants in the case, namely CompUSA.com, Systemax and Tiger Direct.

Late last year, it also settled with Creative Technology and Creative Labs.

The main difference between that settlement and the deal with Amazon, based on the wording of the short press releases, is that Amazon isn’t said to have entered a licensing agreement with the Acacia subsidiary per se.

Terms of the Amazon settlement agreement were, however, not disclosed.