An asterism in Leo, formed from 6 stars. Not one of the 88 constellations.
A backwards question mark ending at Regulus, forming the head and mane of Leo. The Leonid meteors radiate from inside it.
The Sickle is centred near right ascension 10.1 hours, declination +20°. It sits well north on the sky and is comfortably placed for northern hemisphere observers.
The International Astronomical Union recognises 88 constellations, and they divide the whole sky between them like countries on a map. The Sickle is not one of them — it is a pattern picked out of Leo. That makes it an asterism: a shape people recognise and name, with no official standing whatsoever.
The distinction matters less than it sounds. Asterisms are usually easier to find than the constellations containing them, which is exactly why they survive.
SkyRef can draw the Sickle in its real position for wherever you are — switch on the asterism layer and it appears dashed across the constellations it runs through.