Unseen character

Television situation comedies sometimes include continuing characters who are never seen or heard by the audience, but only described by other characters.

Examples:

Heard but not seen:

• Carlton, the doorman on Rhoda
• Captain Mainwaring's wife Elizabeth, in Dad's Army

Neither seen nor heard:

• Vera, Norm Peterson's wife on Cheers
• Maris Crane, ex-wife of Niles Crane, on Frasier
• Karen's husband on Will & Grace
• 'Er Indoors, Arthur Daley's wife in Minder