'sickle-shaped' is a compound of 'sickle' and 'shaped'. 'sickle' originates from Old English 'sicol' (also attested as Middle English 'sikel'), ultimately from a Proto-Germanic form related to Latin 'siculus' (from 'sica'), where 'sica' meant 'dagger' or a short curved blade; 'shaped' derives from Old English 'scapan'/'sceapen' (to form) from Proto-Germanic '*skapjaną' meaning 'to create, form'.

'sickle' changed from Old English 'sicol' and Middle English 'sikel' and eventually became the modern English 'sickle'; 'shape' evolved from Old English 'scapan'/'sceapen' to Middle English 'shapen' and then to modern 'shape', with the past-participial form producing adjectives like 'shaped'.

Initially, 'sickle' referred to the curved cutting tool (with roots meaning 'small dagger' or curved blade) and 'shape' referred to form or creation; combined, 'sickle-shaped' came to mean 'having the form of a sickle' and retains that descriptive sense today.