According to the snack food industry…
Pellet snacks? 
seconded
Only edible pellets I’m aware of are for animals, like you feed them to guinea pigs or get a handful to feed deer at a park.
Snack just means a small amount of food not eaten at normal meal times. It can be whatever the heck you want. And they are conducive to dieting–you just have reduce your meals accordingly. In fact, eating five times a day is very often recommended.
To me, snack has always meant any food that isn’t part of a main meal. Period. Even candy.
Anything that takes the edge off the hunger without being a full meal.
So, “One or more of the above, plus…”
Recently, I purchased a small bowl of fruit during work hours because I was a little hungry. One of the check out gals noted this and asked if I was having lunch.
No, I said, I was just having a snack.
She asked why I didn’t buy a candy bar instead if I was having a snack?
Well, let’s see:
- I like fruit
- It’s healthier
- It’s more filling
- It’s cheaper. Really.
I filed this next to the biddies I’ve known who totally comprehend that people drink tea because they like it, not because they’re ill. Seriously, I’ve known women (it’s always women) who as soon as they see me with a cup of tea get all concerned and ask how long I’ve been feeling sick. Er… based on tea consumption, about 40 years.
Very interesting results! It looks like most of the comments say a snack is anything that’s not a meal, but the votes indicate that some foods are generally considered more snack-like than others. Right now, 76.29% of voters think “Chips, pretzels, popcorn, nuts, cheese and crackers, etc.” are a snack - and how this didn’t get 100%, I have no idea. If that stuff isn’t a snack, nothing is. But only 53.61% think “Candy bars (chocolate, as well as Payday, etc.)” are a snack, and only 39.18% think “Other candy (gummies, hard candies, etc.)” are a snack. That said, I am surprised that candy is scoring as high as it is - even “French fries, nachos, pizza rolls, wings, etc.”, at 49.48%, are trailing candy bars in snackiness.
I’m also curious whether people think the time of day affects whether something is a snack. For instance, I didn’t have any breakfast today, and I was just debating whether I should go grab a snack (specifically, a bagel) or have an early lunch. If I’d had that bagel earlier, I would have considered it breakfast, but at this late hour, it just seems like a snack to me. However, a few of the comments above make me think that some people would consider that a late breakfast, regardless. What do you think?
I would disagree - the 7 course meal was not a snack, it was a late lunch or early dinner. There’s no reason you can’t have three full meals after breakfast. 
All of them except for the “regular food” one.