Definitions
1.NounA railfan, particularly an obsessive one.
Someone with a special interest in a particular topic.
2.NounSomeone with a special interest in a particular topic.
3.NounA device that foams or froths liquid.
A screw-top culinary device that comprises a pressure vessel used to hold a liquid and is charged with a compressed gas, to force the contents out of the nozzle, to create a foam.
4.NounA screw-top culinary device that comprises a pressure vessel used to hold a liquid and is charged with a compressed gas, to force the contents out of the nozzle, to create a foam.