Our waking activities fall within the broad categories of work, leisure, and play. These categories are relative. What one person considers work, another might consider leisure or play. And the context matters: if you have to read a book for work or school, it might fall within work while reading a book of your choosing is leisure.

As we move through our lives, how much time we spend in each category varies. Children have a high proportion of play, while adults have a higher proportion of work. Retirees have more leisure time. But humans of all ages engage in play.

Roger Caillois, a French psychological anthropologist, has divided play into four categories:

1. Agôn (competition). This includes sporting events, racing, board games like chess, video games, and the like. Activities in this category require sustained attention, appropriate training, diligent application, and the desire to win. Source.

2. Alea (chance). This type of play requires chance to be a major component in the outcome. Think roulette, games relying on rolling dice, betting games, etc.

3. Mimicry (simulation). Mimicry involves suspension of reality and illusion — alternative realities are created. Play that falls within this category are dance, theater, and the arts in general. Children’s pretend play also falls within this category.

4. Ilinx (vertigo). The goal of activities in this category include “an attempt to momentarily destroy the stability of perception and inflict a kind of panic on an otherwise lucid mind.” Source. Things like spinning, swinging, racing downhill, and sledding that are enjoyed just for fun. Also included are more structured activities like amusement park rides, tightrope walking, skiing, and mountain climbing.

Sometimes, activities fall within more than one category. Skiing for fun is just ilinx, but skiing in a race adds the component of competition (agôn). Likewise, poker, which is a combination of skill and chance, straddles agôn and alea.