black spot

A subject or area about which little or no information is available.

A fictional judicial device among pirates, consisting of a black circle indicating condemnation.

The spot on a snooker table where the black ball is normally placed.

A fungal disease among plants, particularly roses, that results in black spots on the leaves.

A section of roadway that has been designated as being particularly accident-prone.

A dangerous place or area.

A location with poor radio signal reception, e.g. for mobile phones.