This is the 5137th most frequent Catalan word.
aspa
"Cross" or "X-shaped mark."
In this case, 'aspa' refers to a cross shape, often used in signage to denote prohibition.
La senyal de prohibit està marcada amb una gran aspa vermella.
The no-entry sign is marked with a large red cross.
In this sentence, 'aspa' refers to the blade of a fan.
L'aspa del ventilador està trencada.
The blade of the fan is broken.
Here, 'aspes' refers to the blades of a windmill.