Email spam, also known as junk email or unsolicited bulk email (UBE), is a subset of electronic spam involving nearly identical messages sent to numerous recipients by email. The messages may contain disguised links that appear to be for familiar websites but in fact lead to phishing web sites or sites that are hosting malware. Spam email may also include malware as scripts or other executable file attachments. Definitions of spam usually include the aspects that email is unsolicited and sent in bulk.
What is the name given to the silent electrical discharge between the atmosphere and, for example, trees, ships' masts, steeples and flagpoles?
What is the name given to copper bars arranged in a cylinder, insulated from each other which rotates to connect each section of the armature in turn (in a motor) or to the external current (in a dynamo)?