Subject	English	German
tech.	angle of cone	Kegelwinkel
opt.	base angle of the cone	Basiswinkel des Kegels
math.	body angle of a cone	Kegeloeffnungswinkel
microel.	cone angle of the rays	Winkel des Strahlenbündels
opt.	emergent cone angle of light	Winkel des austretenden Strahlenbündels
opt.	half angle of the acceptance cone	halber Öffnungswinkel eines kegelförmigen Lichtbüschels
opt.	half-angle of the incident cone	halber Aperturwinkel (of light)