Spiky

Spiky is an adjective used to describe objects or forms that have sharp points or projections. It can refer to physical characteristics, such as a surface covered with spikes, and, by extension, to designs or textures that evoke this jagged quality.

In biology, spikes or spines appear on a variety of organisms and structures. Sea urchins and some fish have sharp spines for protection, while porcupines and hedgehogs are covered in modified hair called spines or quills. Many plants feature spines or strong thorns, notably cacti and thistles. The term can also describe features such as the spiny projections on certain insect exoskeletons or plant surfaces that deter herbivory.

In materials science and engineering, spiky features describe surfaces or nanostructures with protruding elements that increase surface area or interaction with other materials. Spiky particles, needles, or bristled textures can influence friction, adhesion, or sensory properties in products and interfaces.

In everyday language, spiky can describe hairstyles, fashion, or imagery that uses pointy elements, such as starbursts with radiating spikes. The related noun spikiness refers to the degree of sharpness or the density of spikes in a given object or pattern.

Etymology: spiky comes from spike, with the -y suffix, attested in English from the early modern period. It is commonly used across disciplines to convey the presence or suggestion of sharp protrusions.