alféizar bedeutet auf Englisch

sill [sills]▼(base of a window)
noun
[UK: sɪl] [US: ˈsɪl]

windowsill▼(the horizontal member protruding from the base of a window frame)
noun
[UK: ˈwɪn.dəʊ.sɪl] [US: ˈwɪndo.ʊ.sɪl]There's a sparrow on the windowsill. = Hay un gorrión en el alféizar de la ventana.