NEW YORK — Merriam-Webster has picked a small but powerful suffix as word of the year: ism.

But not just any ism. The top isms to earn high traffic spikes and big bumps in lookups on the dictionary company’s website in 2015 over the year before are socialism, fascism, racism, feminism, communism, capitalism and terrorism.

“We had a lot on our minds this year,” mused Peter Sokolowski, the Springfield, Mass.-based company’s editor at large, in a recent interview. “It’s a serious year. These are words of ideas and practices. We’re educating ourselves.”

Pinpointing reasons why words go on the run at Merriam-Webster is an educated guess. The dictionary company tracks corresponding news events to link lookups to real life. And its researchers also crunch data in a way that filters out common words frequently looked up year after year after year when making their top annual choices.

Lookups for fascism corresponded to release of video in November showing a white police officer shooting a black teenager in Chicago, and the criminal charges that followed. Merriam-Webster also saw a stronger correlation in heavy traffic on its site for that word and “fascist” and flash points in Republican Donald Trump’s presidential campaign, including reports on his anti-Islam rhetoric.

Lookups of racism were high all year but had two noticeable spikes, one after the South Carolina church shootings and another amid the University of Missouri protests.

Sokolowski said one spike in lookups for feminism came in April and corresponded with reports on an Ohio middle school student who wore a T-shirt with the word on it in a school photo, only to have it digitally blacked out by school administrators.