Im going to guess you are asking what it is. in that case its an eraser.
An eraser is called 'une gomme' (fem.) in French.
eraser = un gomme
gomme a effacer de craie
"C'est une gomme" is French for "It's an eraser."
Gomme means eraser so it is feminine so it can be either une gomme or la gomme.
This word is french and means rubber/eraser.
une gomme
une gomme
an eraser is une gomme, a ruler is une règle.
une gomme (rubber) une table (table)
"Un gomme" in French translates to "an eraser" in English.
An eraser is 'une gomme' (fem.) in French.