TL;DR: perfumes are generally grouped into broad olfactory families — citrus/fresh, floral, woody, gourmand/sweet — based on the notes that dominate the composition. Understanding these families helps you quickly identify what you actually like, instead of testing at random.
Why olfactory families are a useful shortcut
Rather than describing a perfume only by its brand or name, enthusiasts and industry professionals often classify it by its dominant olfactory family. This makes it easier to compare perfumes with each other and quickly spot the ones likely to appeal to you, starting from what you already like.
Fresh / citrus
Lemon, bergamot, grapefruit, sometimes rounded out with aquatic or green notes. This family is perceived as light, clean, energizing — often recommended for everyday, professional, or summer use. It generally lasts less long than heavier families, since its molecules are more volatile.
Floral
Rose, jasmine, iris, peony... This family covers a very wide spectrum, from light and powdery florals to richer, headier ones. It's historically one of the most used families in perfumery, both on its own and combined with other families (floral-woody, floral-fruity).
Woody
Sandalwood, cedar, vetiver, patchouli — warmer notes, often used in the base of a composition to add depth and longevity. A perfume classified as "woody" can range from a dry, mineral profile to a richer, ambery one depending on the other notes it's paired with.
Gourmand / sweet
Vanilla, caramel, tonka bean, cocoa — a family that's grown in popularity more recently, evoking sensations close to pastry or confectionery. It's often cited as one of the "easiest to love" families on first try, but can quickly become cloying if poorly dosed or overapplied.
Compositions almost always blend several families
In practice, very few perfumes belong to a single pure family: most combine a dominant family (say, woody) with a secondary one (say, gourmand), producing composite profiles like "woody-gourmand" or "floral-fruity." Identifying the dominant family of a perfume you already love is often the fastest way to find other perfumes you'll likely enjoy too.