vilkku

Vilkku is a Finnish term that denotes a blinking signal, most commonly referring to a vehicle’s indicator lights or turn signals. In everyday language, vilkku can describe the lamp itself (vilkkuvalko or vilkun valo), the switch used to activate it (vilkun vipu), or the act of signaling (vilkuttaa). The plural vilkut refers to the set of front and rear indicator lamps on a car or motorcycle.

In automotive use, vilkut serve to indicate a driver’s intended direction to other road users. The system typically consists of bulbs or LEDs controlled by a flasher relay or electronic control unit. When a turn is signaled, the affected lamps flash in sequence with a regular tempo. Hazard lights, when activated, cause all four indicators to flash simultaneously.

In addition to vehicles, vilkku is also used in electronics and hobby projects to describe generic blinking circuits that make LEDs or other lights blink for attention, debugging, or decorative purposes. Such circuits are commonly built with transistors, timers, or microcontrollers and are colloquially referred to as vilkkukellot or vilkkukäyttö in Finnish maker communities.

Etymology reflects the verb vilkkua, meaning to flicker or blink. The term is widespread in Finnish usage and appears in technical manuals, driver education, and everyday speech. While the core idea—an intentional, periodic flash—remains constant, the exact meaning can denote the signal lamp, the signaling action, or the signaling device depending on context.