Popcorn Stitch
a cluster of complete stitches worked into one stitch and folded forward, used for bold, defined surface texture

Popcorn stitch groups several complete double crochets into one stitch, then closes the top of the group and folds it forward so it stands out from the fabric like a small dome. Because each stitch in the cluster is finished before the group is closed, popcorns sit more crisply than bobbles, which use incomplete stitches instead.
There's no US/UK split on the name itself, but since popcorns are built from double crochets, remember that US "double crochet" (dc) is UK "treble crochet" (tr) when reading a UK-written pattern.
How to work it
- Work 5 complete double crochets into the same stitch.
- Drop the loop from your hook (don't pull it through anything yet).
- Insert your hook front to back through the top of the first double crochet in the group.
- Pick up the dropped loop and pull it through that stitch. That's one popcorn, and it should fold forward as you tighten it.
When to use it
Use popcorn stitch for bold, well-defined texture: scattered accents across a blanket, a raised motif in a graphghan, or 3D details on amigurumi like eyes or berries. Popcorns sit up more than bobbles, so use them when you want texture that reads clearly from a distance.