Maybe is not a fine definition but ceramic covers covers such compounds made from cristaline structures, with ionic and/or covalent bonding. Some of them are intermetallic and others pure ceramics. Depending of chemical bonding physical/chemical characteristics are obatined (hardens, toughness, electrical/heating conductiveness,...)
Nothing to do with metals also with cristaline structure but electrons are not localised.
Sometimes you can find glasses as ceramics, but it is not correct, although chemicaly are similar, they have vitreous structures.
Combinations are composites trying to obtain best mix of characteristics.
If you have a concrete case?
Regards,