5.4.2 Abbreviated nouns
Some Italian nouns are frequently abbreviated and therefore appear to be of a different gender than they really are. E.g., la foto, la moto. These abbreviated forms are also indeclinable:
la foto = feminine singular; la foto(grafia) singular, le foto(grafie) plural
the photo(graph)/the photographs
la bici = feminine singular; la bici(cletta)/ le bici(clette)
the bike/ the bikes
la moto = feminine singular; la moto(cicletta)/ le moto(ciclette)
the motorcycle/ the motorcycles
la radio = feminine singular; la radio(fonia)/ le radio(fonie)
the radio/ the radios
il cinema = masculine singular; il cinema(tografo) / i cinema(tografi)
the cinema/the cinemas