When it's chilly outside and you need something warm and comforting to help you unwind before bed, there's one drink that hits the spot—a big, hot mug of tisane. You might not recognize the name, but you've had tisanes (pronounced ti-zahns) if you've had mint, rooibos, chamomile, or other herbs and aromatics steeped in hot water. The category is more commonly known as herbal tea, but according to The Kitchn, herbal tea technically isn't tea at all.

Today the word tea is used as a catch-all term for any drink made by soaking plant parts in boiling water, but it actually describes a specific plant species. Camellia sinensis is a kind of evergreen shrub whose leaves and buds are used to make so-called "true tea." True tea includes most caffeinated teas like black tea, white tea, green tea, and their many varieties. Even though these teas vary greatly in taste and appearance, they're just different preparations of the same ingredient. Black tea leaves are oxidized before they're dried, which produces the chemical properties that give the tea its dark color and strong taste. Green and white tea leaves skip the oxidation process, so they're milder in flavor.

Herbal teas are something different all together. They don't come from the C. sinensis plant, and therefore they aren't proper tea. The only similarity lies in how the two "tea" varieties are consumed: by submerging the dried plant matter into water until the flavors infuse the beverage.

The word tisane has been around since the 14th century, and it's the term to use if you want to be completely accurate about what you're drinking. But you can get away with describing your hot drink as "tea" even if there isn't any literal tea in your cup. Herbal tea is so widely used that Merriam-Webster has broadened its definition of tea to include "any of various plants used like tea."