V4

V4 or V-4 may refer to:

Science and technology

LNER Class V4, a class of British steam locomotives
V4 engine, a V engine with four cylinders in two banks of two cylinders
Visual area V4, in the visual cortex
Klein four-group, in mathematics
ITU-T V.4, a telecommunication recommendation
ATC code V04 Diagnostic agents, a subgroup of the Anatomical Therapeutic Chemical Classification System
The V4 JavaScript engine for QML
V₄, one of six precordial leads in electrocardiography
V-4 (rocket launch), first mostly-successful launch of the V-2 rocket

Visegrád Group, an alliance of four Central European states - Czech Republic, Hungary, Poland and Slovakia
Rheinbote or V-4, a German World War II four-stage missile
Saint Kitts & Nevis (ITU prefix)
Vieques Air Link (IATA airline code)
V4, a grade (climbing) for difficulty of a boulder climbing route