“Socialism” was the most looked-up word on Merriam-Webster’s site this year, a change the American dictionary publisher attributes to US presidential candidate Bernie Sanders, who has positioned of himself as a “democratic socialist”.

Last year, “culture” was the dictionary’s top word; this year, socialism sparked “intense” curiosity, with an increase of 169% in look-ups compared to 2014, according to the dictionary. “Socialism has been near the top of our online dictionary look-up list for several years,” said editor-at-large Peter Sokolowsk. “However, this year look-ups for socialism moved up even further, beginning with the July campaign events for Bernie Sanders, remaining high throughout the following months and spiking again after the first Democratic debate in October.”

Merriam-Webster said that the fact that Sanders has embraced socialism “shows the term has moved beyond its cold war associations”. It has now included new information in its dictionary entry for the term, writing: “In the modern era, ‘pure’ socialism has been seen only rarely and usually briefly in a few communist regimes. Far more common are systems of social democracy, now often referred to as ‘democratic socialism’, in which extensive state regulation, with limited state ownership, has been employed by democratically elected governments (as in Sweden and Denmark) in the belief that it produces a fair distribution of income without impairing economic growth.”

Socialism is not the dictionary’s word of the year, though – that honour goes for the first time to a suffix, “ism”, reflecting the fact that many of Merriam-Webster’s most-looked-up words in 2015 ended in “ism”. These include “fascism” – which saw a spike in look-ups following Donald Trump’s remarks about banning Muslims from entering the US – and “terrorism”, looked up frequently following the Paris, Colorado Springs and San Bernardino attacks.

“In November,” said the dictionary, “some conservatives began using ‘fascist’ to describe Trump’s proposals and style, and at the beginning of December, writers for Slate and the New York Times and a commentator on CNN all referred to Trump as a fascist, sending many people to the dictionary.”

“Racism” look-ups increased by 50% over last year, prompted by the South Carolina church shooting, the University of Missouri protests and incidents of police violence, while “feminism” also saw a spike in searches thanks to “Amy Schumer’s success, Hillary Clinton’s candidacy and coverage of Caitlyn Jenner’s story”.

Two more -isms – “communism” and “capitalism” – complete a list of seven words that represent “millions of individual look-ups” over the last year.

Previous words of the year at Merriam-Webster include “democracy” in 2003, “blog” in 2004 and “w00t” in 2007. Earlier this month, Oxford Dictionaries named the “tears of joy” emoji as their “word” of the year.