Belgium
GSM
Meaning
a mobile phone
Elsewhere
portable
Explanation
France says portable. Belgium, Luxembourg and Réunion named the phone after the network standard it ran on.
Example
J’ai oublié mon GSM sur la table du salon.
I've left my mobile on the living room table.
Origin
The English acronym for global system for mobile communications, the network standard.
Where
Belgium
Luxembourg
Réunion
Source