You’re not crazy. The words premium and snack really are popping up on chain-restaurant menus everywhere. Crazy is making some appearances too.

Why are these the latest restaurant buzzwords? And why are they supposed to resonate with customers? Let’s take a look.

Crazy

Sensible food is boring. Fast-food fans — young ones especially — supposedly want something different, something a little, well, crazy. A Fortune post noted that crazy and similar terms have accordingly been showing up on chain-restaurant menus. Most obviously, there’s Pizza Hut’s new Crazy Cheesy Crust Pizza, which features 16 dough pockets stuffed with extra cheese around the pizza — a design that indeed seems pretty crazy.

Why has crazy become the menu term du jour? “What’s happening is that the American palate has moved from boring to bold,” Nancy Brown, a partner at branding firm CBX, told Fortune. “I think crazy is what extreme was because extreme has kind of run its course.”

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One of the fast-food players known for being “extreme” a few years back was Pizza Hut’s sister at Yum Brands, Taco Bell. The chain began offering items like the Extreme Cheese and Beef Quesadilla in the late ’00s. It has since moved on to menu offerings that are “crazy,” or more precisely “loco,” with last year’s introduction of the highly successful Doritos Locos Taco.

Premium

A 2011 Technomic report found that premium was the most persuasive menu term for getting customers to order an item with beef; 28% of surveyed consumers said they’d be more likely to order beef with the word premium, and they’d be willing to pay a 5% premium for their premium order. Well, surprise, surprise, a study conducted by Mintel for BurgerBusiness last year reported that usage of the word premium on restaurant-chain menus has soared. By its count, there were 138 “premium” offerings on chain menus last year, compared with just 69 in 2007.

The word premium “connotes high quality or high price without committing to being either,” BurgerBusiness noted. “Premium sounds upscale, special, with a sophistication that deluxe lacks.”

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Today’s fast-food “premium” selections go well beyond beef. In a recent count at the McDonald’s menu, there were 12 “premium” sandwiches and wraps, plus nine “premium” salads, as well as “premium” roast coffee and “premium” roast iced coffee. Burger King, meanwhile, boasts the Premium Alaskan Fish Sandwich, and Sonic Drive-In has a lineup of “premium beef” hotdogs.

Snack

Snack has been proliferating at restaurants for several years now, with usage of the word tripling from 2007 to 2010 on fast-food menus. McDonald’s now has 10 varieties of “snack wraps” and snack-size orders of items like Fish McBites. For that matter, bites, a word that signifies food that’s easy for snacking, is also popular on menus — Pretzelmaker Bites, KFC Original Recipe Bites and so on.

Why the rise in menu items that aren’t quite meals? One reason is that restaurants are trying to attract customers during the normally dead moments of the day that aren’t quite mealtimes — the in-between hours when diners aren’t up for a full meal, but could go for a quick snack. Snacks can also serve as up-sell items that customers add on in addition to their meal order. And, most of all, snack is spreading because the word is appealing to consumers on two key levels: it’s easy on the waistline and wallet alike. It’s “just a snack,” after all.

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Nation’s Restaurant News reported that Arby’s is now testing the possibility of launching a “snack ’n’ save” menu as a replacement for its value menu — value being another buzzword that fast-food customers are well acquainted with.